Managing gut health – a key challenge in ABF broiler production

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by Ajay Bhoyar, Global Technical Manager Poultry, EW Nutrition

Gut health is a critical challenge in antibiotics-free (ABF) production as it plays a vital role in the overall health and well-being of animals. Antibiotics have long been used as a means of preventing and treating diseases in animals, but their overuse has led to the development of antibiotic-resistant bacteria. As a result, many farmers and producers are shifting towards antibiotics-free production methods. This shift presents a significant challenge as maintaining gut health without antibiotics can be difficult. It is, however, not impossible.

One of the main challenges in antibiotics-free production is the prevention of bacterial infections in the gut. The gut microbiome plays a crucial role in the immune system and overall health of animals. When the balance of microbes in the gut is disrupted (dysbiosis), it can lead to poor nutrient absorption which subsequently results in reduced live bird performance including feed efficiency and weight gain in broiler chicken. In the absence of antibiotics, farmers and producers must rely on other methods to maintain a healthy gut microbiome.

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Antibiotic reduction – a major global trend

The trend in recent years has been for poultry producers to reduce their use of antibiotics to promote public health and improve the sustainability of their operations. This has been driven by concerns about the development of antibiotic-resistant bacteria and the potential impact on human health, as well as by consumer demand for meat produced without antibiotics. Many countries now have regulations in place that limit the use of antibiotics in food and animal production.

Challenges to antibiotics-free poultry (ABF) production

  1. Disease control. Antibiotic-free poultry production requires farmers to rely on alternative methods for controlling and preventing diseases, such as stepped-up biosecurity practices. This can be more labor-intensive and costly.
  2. Higher mortality rates. Without antibiotics, poultry farmers may experience higher mortality rates due to disease outbreaks and other health issues. This can lead to financial losses for the farmer and a reduced supply of poultry products for consumers.
  3. Feeding challenges. Antibiotic growth promotors (AGPs) are often used in feed to promote growth and prevent intestinal disease in poultry. Without AGPs, poultry producers can find alternative ways to ensure expected production performance.
  4. Increased cost. Antibiotic-free poultry production can be more expensive than conventional production methods, as farmers must invest in additional housing, equipment, labor, etc.

Phasing out AGPs will likely lead to changes in the microbial profile of the intestinal tract. It is hoped that strategies such as infectious disease prevention programs and using non-antibiotic alternatives minimize possible negative consequences of antibiotic removal on poultry flocks (Yegani and Korver, 2008).

Gut health is key to overall health

A healthy gastrointestinal system is important for poultry to achieve its maximum production potential. Gut health in poultry refers to the overall well-being and functioning of the gastrointestinal tract in birds. This includes the balance of beneficial bacteria, the integrity of the gut lining, and the ability to digest and absorb nutrients. Gut health is important for maintaining the overall health and well-being of the birds. A healthy gut helps to improve feed efficiency, nutrient absorption, and the overall immunity of the birds.

The gut is host to more than 640 different species of bacteria and 20+ different hormones. It digests and absorbs the vast majority of nutrients and makes up for nearly a quarter of body energy expenditure. It is also the largest immune organ in the body (Kraehenbuhl and Neutra, 1992). Consequently, ‘gut health’ is highly complex and encompasses the macro and micro-structural integrity of the gut, the balance of the microflora, and the status of the immune system (Chot, 2009).

Poultry immunity is mediated by the gut

The gut is a critical component of the immune system, as it is the first line of defense against pathogens that enter the body through the digestive system. Chickens have a specialized immune system in the gut, known as gut-associated lymphoid tissue (GALT), which helps to identify and respond to potential pathogens. The GALT includes Peyer’s Patches, which are clusters of immune cells located in the gut wall, as well as the gut-associated lymphocytes (GALs) that are found throughout the gut. These immune cells are responsible for recognizing and responding to pathogens that enter the gut.

The gut-mediated immune response in chickens involves several different mechanisms, including the activation of immune cells, the production of antibodies, and the release of inflammatory mediators. The GALT and GALs play a crucial role in this response by identifying and responding to pathogens, as well as activating other immune cells to help fight off the infection.

The gut microbiome also plays a critical role in gut-mediated immunity in chickens. The gut microbiome is made up of a highly varied community of microorganisms, and these microorganisms can have a significant impact on the immune response. For example, certain beneficial bacteria can help to stimulate the immune response and protect the gut from pathogens.

Overall, the gut microbiome, GALT, and GALs all work together to create an environment that is hostile to pathogens while supporting the growth and health of beneficial microorganisms.

Dysbiosis/Dysbacteriosis impacts performance

Dysbiosis is an imbalance in the gut microbiota because of an intestinal disruption. Dysbacteriosis can lead to wet litter and caking issues. Prolonged contact with the caked litter can lead to pododermatitis (feet ulceration) and hock-burn, resulting in welfare issues as well as degradation of the carcass (Bailey, 2010). Apart from these issues, the major economic impact comes from reduced growth rates, FCR, and increased veterinary treatment costs. Coccidiosis infection and other enteric diseases can be aggravated when dysbiosis is prevalent. Generally, animals with dysbiosis have high concentrations of Clostridium that generate more toxins, leading to necrotic enteritis.

FigureFig.1: Dysbiosis – a result of challenging animal’s microbiome. Source: Charisse Petersen and June L. Round. 2014

It is believed that both non-infectious and infectious factors can play a role in dysbacteriosis (DeGussem, 2007). Any changes in feed and feed raw materials, as well as the physical quality of feed, influence the balance of the gut microbiota. There are some risk periods during poultry production when the bird will be challenged, for example during feed change, vaccination, handling, transportation, etc. During these periods, the gut microbiota can fluctuate and, in some cases, if management is sub-optimal, dysbacteriosis can occur.

Infectious agents that potentially play a role in dysbacteriosis include mycotoxins, Eimeria spp., Clostridium perfringens, and other bacteria producing toxic metabolites.

Factors affecting gut health

The factors affecting broiler gut health can be summarized as follows:

  1. Feed and water quality: The form, type, and quality of feed provided to broilers can significantly impact their gut health. Consistent availability of cool and hygienic drinking water is crucial for optimum production performance.
  2. Stress: Stressful conditions, such as high environmental temperatures or poor ventilation, can lead to an imbalance in the gut microbiome and an increased risk of disease.
  3. Microbial exposure: Exposure to pathogens or other harmful bacteria can disrupt the gut microbiome and lead to gut health issues.
  4. Immune system: A robust immune system is important for maintaining gut health, as it helps to prevent the overgrowth of harmful bacteria and promote the growth of beneficial bacteria.
  5. Sanitation: Keeping the broiler environment clean and free of pathogens is crucial for maintaining gut health, as bacteria and other pathogens can easily spread and disrupt the gut microbiome.
  6. Management practices: Proper management practices, such as proper feeding and watering, and litter management can help to maintain gut health and prevent gut-related issues.

Chat GutFig. 2. Key factors affecting broilers’ gut health

Key approaches for managing gut health without antibiotics

Two key approaches for managing gut health in poultry without the use of antibiotics are outstandingly successful.

Proper nutrition and management practices

Ensuring the birds have access to clean water, high-quality feed, and a stress-free environment is crucial for ABF poultry production. A balanced diet in terms of protein, energy, and essential vitamins and minerals is essential for maintaining gut health.

The environment in which birds have kept plays a major role in maintaining gut health. Proper sanitation and ventilation, as well as the right temperature and humidity, are crucial to prevent the spread of disease and infection. There is no alternative to the strict implementation of stringent biosecurity measures to prevent the spread of disease.

Early detection and treatment of diseases can help to prevent them from becoming more serious problems affecting the profitability of ABF production. It is important to keep a close eye on birds for signs of disease, such as diarrhea, reduced water, and feed consumption.

Gut health-promoting feed additives

Another approach to maintaining gut health in antibiotics-free poultry production is using gut health-supporting feed additives. A variety of gut health-supporting feed additives including phytochemicals/essential oils, organic acids, probiotics, prebiotics, exogenous enzymes, etc. in combination or alone are used in animal production. Particularly, phytogenic feed additives (PFAs) have gained interest as cost-effective feed additives with already well-established effects on improving broiler chickens’ intestinal health.

Plant secondary metabolites and essential oils (generically called phytogenics, phytochemicals, or phytomolecules) are biologically active compounds that have recently garnered interest as feed additives in poultry production, due to their capacity to improve feed efficiency by enhancing the production of digestive secretions and nutrient absorption. This helps reduce the pathogenic load in the gut, exert antioxidant properties and decrease the microbial burden on the animal’s immune status (Abdelli et al. 2021).

Plant extracts – Essential oils (EOs) /Phytomolecules

Phytochemicals are naturally occurring compounds found in plants. Many phytomolecules have been found to have antimicrobial properties, meaning they can inhibit the growth or kill microorganisms such as bacteria, viruses, and fungi. Examples of phytomolecules with antimicrobial properties include compounds found in garlic, thyme, and tea tree oil. Essential oils (EOs) are raw plant extracts (flowers, leaves, roots, fruit, etc.) whereas phytomolecules are active ingredients of essential oils or other plant materials. A phytomolecule is clearly defined as one active compound. Essential oils (EOs) are important aromatic components of herbs and spices and are used as natural alternatives for replacing antibiotic growth promoters (AGPs) in poultry feed. The beneficial effects of EOs include appetite stimulation, improvement of enzyme secretion related to food digestion, and immune response activation (Krishan and Narang, 2014).

A wide variety of herbs and spices (thyme, oregano, cinnamon, rosemary, marjoram, yarrow, garlic, ginger, green tea, black cumin, and coriander, among others), as well as EOs (from thymol, carvacrol, cinnamaldehyde, garlic, anise, rosemary, citruses, clove, ginger), have been used in poultry, individually or mixed, for their potential application as AGP alternatives (Gadde et al., 2017).

Table DataFig. 3: Phytomolecule-based feed additive outperforms AGPs with improved broiler performance (42 Days field study)

One of the primary modes of action of EOs is related to their antimicrobial effects which allow for controlling potential pathogens (Mohammadi and Kim, 2018).

Phytomolecule blend  Clostridium perfringens Enterococcus caecorum Enterococcus hirae Escherichia coli Salmonella typhimurium  Staphylococcus aureus
Ventar D 1250 2500 5000 2500 5000 2500

Fig. 4: Effectivity of phytomolecule-based feed additive (Ventar D) against enteropathogenic bacteria (MIC value in PPM)

Phytomolecules have been shown to have anti-inflammatory properties. These compounds include flavonoids, polyphenols, carotenoids, and terpenes, among others. One of the ways in which phytomolecules exhibit anti-inflammatory effects is through their ability to inhibit the activity of pro-inflammatory enzymes and molecules. For example, polyphenols have been shown to inhibit the activity of nuclear factor-kappa B (NF-kB), a transcription factor that plays a key role in regulating inflammation.

Phytomolecules also have antioxidant properties, which can help to protect cells from damage caused by reactive oxygen species (ROS) and other reactive molecules that can contribute to inflammation. Plant extracts are also proposed to be used as antioxidants in animal feed, protecting animals from oxidative damage caused by free radicals. The presence of phenolic OH groups in thymol, carvacrol, and other plant extracts act as hydrogen donors to the peroxy radicals produced during the first step in lipid oxidation, thus retarding the hydroxyl peroxide formation (Farag et al., 1989, Djeridane et al., 2006). Thymol and carvacrol are reported to inhibit lipid peroxidation (Hashemipour et.al. 2013) and have strong antioxidant activity (Yanishlieva et al., 1999).

Overall, the anti-inflammatory effects of phytomolecules are thought to be due to a combination of their ability to inhibit the activity of pro-inflammatory enzymes and molecules, their antioxidant properties, and their ability to modulate the immune system. Plant extracts (i.e. carvacrol, cinnamaldehyde, eugenol. etc.) inhibit the production of pro-inflammatory cytokines and chemokines from endotoxin-stimulated immune cells and epithelial cells (Lang et al., 2004, Lee et al., 2005, Liu et al., 2020). It has been indicated that anti-inflammatory activities may be partially mediated by blocking the NF-κB activation pathway (Lee et al., 2005).

Table DataFig. 5: Anti-inflammatory effect of phytomolecule-based feed additive (Ventar D) – the reduced activity of inflammatory cytokines

Proper protection of EOs/Phytomolecules is key to optimum results

Several phytogenic compounds have also been shown to be largely absorbed in the upper GIT, meaning that without proper protection, the majority would not reach the lower gut where they would exert their major functions (Abdelli et al. 2021). The benefits of supplementing the broiler diet with a mixture of encapsulated EOs were higher than the tested PFA in powdered, non-protected form (Hafeez et al. 2016). Novel delivery technologies have been developed to protect PFAs from the degradation and oxidation process during feed processing and storage, ease the handling, allow a slower release, and target the lower GIT (Starčević et al. 2014). The specific protection techniques used during the commercial production of an EO/phytomolecule blend are crucial in delivering on all the objectives with remarkable consistency.

Table Data

Fig. 6: Pelling stability of phytomolecule – based feed additive (Ventar D) at high temperature and longer conditioning time

Phytomolecule blend optimizes production performance

Removal of antibiotics in poultry production can be challenging for controlling mortality and maintaining the production performance of the birds. Phytogenic feed additives have been shown to improve the production performance of chicken due to their antimicrobial, anti-inflammatory, antioxidant, and digestive properties. Possible mechanisms behind improved nutrient digestibility by phytogenic feed additives (PFAs) supplementation could be attributed to the ability of these feed additives to stimulate appetite, saliva secretion, intestinal mucus production, bile acid secretion, and activity of digestive enzymes such as trypsin and amylase as well as to positively affect the intestinal morphology (Oso et al. 2019). EOs are perceived as growth promoters in poultry diets with strong antimicrobial and anticoccidial activities. showed that PFAs have positive effects on body weight gain and FCR in chickens (Khattak et al. 2014, Zhang et al. 2009). EOs are perceived as growth promoters in poultry diets, with strong antimicrobial and anticoccidial activities (Zahi et al., 2018). PFAs have positive effects on body weight gain and FCR in chickens (Khattak et al. 2014, Zhang et el. 2009).

Table Data
Fig. 7: Phytomolecule-based feed additive improved broiler FCR and mortality in field trial


In conclusion, managing gut health is a significant challenge in ABF broiler production that must be addressed to achieve optimal performance and welfare of the birds. The use of antibiotics as a preventative measure in broiler production has been widely used, but with the increasing demand for antibiotic-free products, alternative methods to maintain gut health must be implemented. These include using gut health-supporting feed additives, and proper management practices such as implementing biosecurity measures, maintaining optimal environmental conditions, providing adequate space and ventilation, and reducing stress. However, it is essential to note that there is no one-size-fits-all solution for gut health management in ABF broiler production. It is important to continuously monitor and assess their flock’s gut health and make adjustments as necessary. Additionally, research and development in this field should be encouraged to identify new and innovative ways to maintain gut health in ABF broiler production.

Overall, managing gut health is a critical challenge that requires a multi-faceted approach and ongoing monitoring and management. By implementing the appropriate strategies and utilizing new technologies, poultry operators can ensure the health and well-being of their flocks while meeting the growing demand for antibiotic-free products sustainably.


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Antibiotic reduction with high performance: Can swine operations do it?

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by  Inge Heinzl and Fellipe Freitas Barbosa, EW Nutrition

According to the American Medical Association, antimicrobial resistance is one of the main threats to public health nowadays. More than 2 million people are infected with bacteria resistant to different types of antibiotics every year (Marquardt and Suzhen, 2018). Prof Dame Sally Davies (2012), Chief Medical Officer for England, mentions that antibiotics are losing their effectiveness at alarming rates. Bacteria are finding ways to survive the antibiotics, so these molecules no longer work. O’Neill (2016) predicted in his report that 10 million people a year could be dying by 2050 due to antimicrobial resistance.

piglets farm

Antimicrobial resistance is a natural process but this is accelerated by inappropriate prescribing of antimicrobials, poor infection control practices and the unnecessary use of antimicrobials in agriculture (Barber and Sutherland, 2017).

Antimicrobial resistance – a threat to humanity

Resistance to specific antibiotics occurs through mutations that enable the bacteria to withstand an antibiotic treatment. One mechanism is the production of enzymes degrading or altering the antibiotic, rendering them harmless. The elimination of entrances for antibiotics or the development of pumps discharging them is another possibility. A further option is the elimination of the targets the antibiotic would attack.

So-called “resistance genes” are responsible for resistance. These genes can be transferred from one bacterium to another and also from beneficial bacteria to harmful ones. When antibiotics are used, “normal” bacteria are killed; the resistant ones survive and have all possibilities to proliferate. The Dutch Government has been tracking resistant bacteria in poultry flocks for the last two decades. A clear correlation between antibiotic use and the percentage of resistance could be observed. The good thing: according to the 2020 MARAN report (De Greeff et al., 2020), by reducing the use of antibiotics, the occurrence of resistances can be pushed back.

Antimicrobial resistance – a threat to humanity bar graph

Figure 1. Sales of antibiotics from 1999 to 2016 and the development of resistances (MARAN report, 2018)

Antibiotic use in animal production

In pig production, antibiotics are often used in stressful situations such as weaning or moving. Antibiotics decrease the pathogenic pressure in animals and help them overcome these critical periods. Disadvantage: Antibiotics do not differentiate between good and bad but between susceptible and resistant. Therefore, also the beneficial gut flora gets destroyed through antibiotic treatment, and resistance is spread.

After the ban of antibiotic growth promoters in Europe in 2006, the US has also made considerable efforts to reduce the use of antibiotics.

Is performance at risk without antibiotics?

When antibiotics are taken out of livestock production, measures in different areas must be implemented to keep performance and profitability high. Without supporting the animals by other means, they will get sick and even die in acute cases. Subclinical disease forms reduce their feed intake, and growth performance consequently decreases. According to literature, losses due to decreased average weight gain can be up to $40 per pig (Hao et al., 2014).

Goal: reducing antibiotics while maintaining performance

To support pigs, especially during the afore-mentioned critical periods, alternatives focusing on the maintenance of gut health and, therefore, also overall health must be chosen. This goal can only be achieved by balancing the intestinal flora with reducing pathogenic bacteria occurrence.

Phytomolecules are an effective solution

Phytomolecules are produced by plants to defend themselves against predators or pathogens. Farmers use the substances in animal feeds to support digestion, improve palatability, but also to reduce pathogenic pressure (Baser and Buchbauer, 2010).

In animal feeding, different application forms are available:

  • As premixes containing microencapsulated phytomolecules with a slow release. This version is mixed into the feed in the feed mill and constitutes continuous long-term support for the animals. Due to microencapsulation, the active substances are released where they are needed – in the gut.
  • As liquid complementary feeds for the application via the waterline. The application of the liquid form to the animals can be decided from one day to the other. It is an optimal additional tool to support the pigs in challenging situations such as weaning.

Scientific trials show: In-feed phytomolecules support performance

A trial conducted at the Federal University of Lavras (Brazil) evaluated if phytomolecules as a regular diet component can deliver the same effects on growth performance as AGPs in pig production.

For the trial, 108 castrated newborn male pigs were allocated to 3 groups (control, AGP (antibiotic growth promoters), and Activo). Pigs were weaned at 23 days of age with an average weight of 6.3 kg. They were fed a 3-phase diet (nursery, growing, and finishing). The inclusion rates of the additives (antibiotics and phytomolecules-based product – Activo) are shown in table 1.

On days 0, 1, and 2 of the experiment, the animals were challenged by applying a solution containing 107 CFU of E. coli K88, producing the toxins LT, Sta, and bST. Additionally, during the two last days before the growing phase, the animals were exposed to 5h of heat stress, using infrared lamps and closed windows. The parameters weight gain, final weight, FCR, and gut flora composition in the cecum were evaluated.

Phase Control AGP Activo
Nursery 0-7 days Gentamycin 2.7kg/t 0.4kg/t
8-42 days Haloquinol 0.2kg/t 0.3kg/t
Growing 42-52 days Tylosin 0.45kg/t 0.4kg/t
53-87 days Enramycin 0.125kg/t 0.2kg/t
Finishing 88-97 days Tylosin 0.45kg/t 0.4kg/t
98-126 days Enramycin 0.063kg/t 0.2kg/t

Table 1. Inclusion rate of the additives in the feed
AGP: Antibiotic growth promoter; Activo: product based on phytomolecules, microencapsulated (EW Nutrition)


The results of this trial are shown in figure 2.

Concerning growth performance, the group fed the phytomolecules-based product Activo showed a 4.36 kg higher final weight after 126 days than the group provided AGPs (p=0.11), resulting in a 3.28 kg higher weight gain (p=0.21) and a 13 points better feed conversion.

Data of growth performance including final weight, weight gain and FCR

Figure 2. Data of growth performance including final weight, weight gain and FCR adjusted to 100kg

The evaluation of some bacteria naturally occurring in the gut flora showed that, in contrast to the antibiotic prophylaxes, Activo has no negative impact on E. coli, Lactobacillus and Bifidobacterium. However, the antibiotic group showed a slight decrease in the population of Lactobacilli (Figure 3).

Impact of antibiotics and phytomolecules (Activo) on the composition of the gut flora

Figure 3. Impact of antibiotics and phytomolecules (Activo) on the composition of the gut flora

This trial shows Activo increasing growth performance and feed conversion without any negative impact on gut flora. The addition of phytomolecules (Activo) to the feed is documented as optimal long-term support instead of antibiotic growth promoters.

Trial shows: Phytomolecules support animals in critical situations like weaning

In a trial conducted in the USA, a product containing phytomolecules and organic acids (Activo Liquid, EW Nutrition) was compared to an antibiotic for controlling bacterial diseases in US pig production (Mecadox). For the trial, a total of 360 weanling pigs, about 19 days old and weighing 5.70 kg, were divided into four groups. Each group consists of 9 pens with 10 animals per pen. All groups were fed a 3-phase diet.

To the different trial groups, the following products were added (table 2):

Feeding valid for all groups Group / Product Inclusion rate and period of application
3-phase feeding after weaning: Mecadox 50 g/t of feed during the whole period
Phase I (days 0-7): 23 % CP, 5.4 % CF Activo Liquid 3 375 ml/1000 L of water for 3 days post-weaning
Phase II (days 8-21): 21 % CP, 4.1 % CF Activo Liquid 5 375 ml/1000 L of water for 5 days post-weaning
Phase III (days 22-42): 19 % CP, 4.4 % CF Activo Liquid 7 375 ml/1000 L of water for 7 days post-weaning

These performance parameters were evaluated: live weight, daily gain, daily feed intake, feed:gain ratios, and mortality.

Table 2. Feeding and inclusion of the additives


The results of the trial are shown in figure 4. Concerning growth, no significant differences could be seen between the groups, only numerical differences. Live weight in the antibiotic group was 25.95 kg, and in the Activo Liquid groups, it ranges from 25.77 kg (shortest period of application) to 26.20 kg (see below). This resulted in calculated values for an average daily gain of 473 g in the Mecadox fed animals and 463 to 487g in the Activo Liquid groups. Due to a lower feed intake per kg of weight gain, all groups fed Activo Liquid showed a significantly (p=0.05) better feed conversion than the Mecadox group.

Antibiotic Mecadox and the phytomolecules-based product Activo Liquid for different periods

Figure 4. Live weight in the groups fed the antibiotic Mecadox and the phytomolecules-based product Activo Liquid for different periods
Average daily gain in the different trial groups
Average daily feed intake in the different trial groups (P=0.05)

Concerning mortality, the group fed Activo Liquid for 5 days showed the lowest mortality rate of 1.1% (figure 5).

lowest mortality rate of 1.1%

Figure 5. Feed:gain ratio in the different trial groups (P=0.05) & Mortality rates

Considering all parameters, the group fed Activo Liquid for five days provided the best results: numerically the lowest mortality rate, highest daily gain, and one of the two lowest feed:gain ratios. This trial concludes that Activo Liquid with an application period of five days can safely replace antibiotic growth promoters in the diet. Therefore, Activo Liquid is an interesting tool to additionally support pigs during critical periods of life.

Phytomolecules help keep health and performance together

The trials conducted with two types of phytomolecules-based products show that phytomolecules efficiently support pigs to achieve their genetic potential. A basic supply of these substances within the feed yields results similar to those of animals receiving antibiotic growth promoters (AGPs). In challenging situations like weaning, additional short-term supply is recommended, which can be done with liquid products via the waterline.

With this strategy, the use of antibiotic growth promoters and, therefore, antibiotics in general can be drastically reduced. This approach can help decrease antimicrobial resistance and, not to be forgotten, accommodates final customers’ requests for the lower usage of antibiotics in livestock.


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De Greeff, S.C., A.F. Schoffelen, and C.M. Verduin. “MARAN Reports.” WUR. National Institute for Public Health and the Environment – Ministery of Health, Welfare and Sport, June 2020. https://www.wur.nl/en/Research-Results/Research-Institutes/Bioveterinary-Research/In-the-spotlight/Antibiotic-resistance/MARAN-reports.htm.

Hao, Haihong, Guyue Cheng, Zahid Iqbal, Xiaohui Ai, Hafiz I. Hussain, Lingli Huang, Menghong Dai, Yulian Wang, Zhenli Liu, and Zonghui Yuan. “Benefits and Risks of Antimicrobial Use in Food-Producing Animals.” Frontiers in Microbiology 5, no. Art. 288 (2014): 1–11. https://doi.org/10.3389/fmicb.2014.00288.

Marquardt, Ronald R, and Suzhen Li. “Antimicrobial Resistance in Livestock: Advances and Alternatives to Antibiotics.” Animal Frontiers 8, no. 2 (2018): 30–37. https://doi.org/10.1093/af/vfy001.

O’Neill, J. “Tackling Drug-Resistant Infections Globally.” Review on Antimicrobial Resistance. Wellcome Trust / HM Government, May 19, 2016. https://amr-review.org/sites/default/files/160518_Final%20paper_with%20cover.pdf.

Two pandemics. How antimicrobial resistance will eventually overshadow COVID-19

picture 1 coronavirus shutterstock

by Dr. Inge Heinzl – EW Nutrition

Since early 2020, COVID-19 has been keeping the world under a cloud of uncertaintyWith all eyes focused on this pandemic, we nevertheless must not forget that anothersilent pandemic is developing: antimicrobial resistance (AMR). Unfortunately, the COVID-19 could easily exacerbate the AMR pandemic.   

How antimicrobial resistance will eventually overshadow COVID-19

What is the relationship between COVID-19 and AMR? 

The COVID-19 pandemic, as well as AMR, have a direct health impact on people: they get ill, suffer from its short- and long-term effects, or even die. AMR, on the other hand, is not a disease in itself but makes various bacterial infections difficult to treat and is considered a pandemic due to its dramatic global scope (Cars et al., 2021). Both pandemics, the ‘loud’ COVID-19 and the ‘silent’ AMR pandemic, are monitored by official institutions. Still, for both, significant uncertainties around actual case figures exist, especially in low-income countries. 

Beginning in China in around December 2019, SARS-CoV-2 spread to the rest of the world within a few months. Figures collated by the WHO show over 250 million confirmed cases and over 5 million deaths to date, with excess mortality rates indicating this to be an underestimation. Quantifying the death toll due to AMR is far more challenging, as disease conditions vary, resistant bacteria go undetected, or the causative pathogens are not identified in the first place (Giattino et al., 2021).

World Mortality Dataset

O’Neill (2014) reported about 700,000 people dying from infections with resistant pathogens every year. He forecasted that, by 2050, 10 million people per year will die if we dont change anything. This figure would represent twice the number of people who died from COVID-19 within the last two years.  In the US and the EU, according to CDC, antibiotic resistance causes 23,000 and 25,000 deaths per year, respectively. In Thailand, 38,000 deaths are attributable to ABR. And in India, 58,000+ babies died from infections with resistant bacteria, usually passed on from their mothers. 

Woerther et al. (2013) note a continuous increase of resistant strains globally. In 2010/11, ESBL carriage rates of 3 to 20 % were the “norm”, but some WHO regions already showed 60 to 70% carriage rates by 2011. In the US, 223,900 cases of Clostridium difficile occurred in 2017, and at least 12,800 people died (CDC, 2019). 

As in the case of SARS-CoV-2, the spread of AMR organisms can be prevented by hygiene measures. Except for hospital settings reported in developed countriesthe spread of resistant bacteria is invisible. Regardless of how little we know about it from official reports, there are indications that bacteria resistance is ubiquitous, triggered to a large extent by the (over)use of antibiotics in community settingsMoreover, it is far more difficult to identify that a patient suffers from AMR infection than from SARS-CoV-2. The latter is easily detected with widespread testing systems, including self-testing.  

COVID and AMR have severe economic consequences 

Besides claiming many lives, both COVID and AMR increase the costs for healthcare. Additionally, due to high sickness ratios and lockdowns, economic losses are tremendous. For COVID as well as for AMR patients, the hospitals need specialized systems and procedures (ventilation apparatus, extraordinary hygiene measures) and specially qualified personnel to treat the infected persons. In addition to the cases of infection, mental illness increases due to these exceptional circumstances. 

US study extrapolates ten-figure costs due to AMR 

In a US cohort study based on records of 25,000 patients from 2007-2015, Nelson et al. (2021a) calculated the treatment costs for infections with methicillin-resistant Staphylococcus aureus or carbapenem-resistant Acinetobacter to be $4.6 billion.  

Another study done by Nelson et al. (2021b) with 87,509 elderly patients suffering from infections with the same resistant pathogens showed estimated costs of $1.9 billion, with 11,852 deaths and 448,224 inpatient days. In these two studies, only two resistant bacteria species were considered – and they alone triggered costs of more than 4 billion US dollars. 

Estimation of COVID costs shows long-lasting negative economic impact 

In the case of COVID, an estimation done by Tan-Torres Edejer et al. (2020) yielded $52.45 billion in added healthcare costs worldwide over four weeks in a status quo scenario. The costs would increase/decrease if the transmission increases/decrease. More detailed consideration is provided by Cutler and Summers (2020).   

Category Cost (billions) in USD
Lost GDP 7592
Health loss
  • Premature death
  • Long-term health impairment
  • Mental health impairment
Total 16121
% of annual GDP 90

Estimated Projected health cost of the COVID-19 crisis (Cutler and Summers, 2020)  

Economic losses due to Corona are tremendous – What about losses due to AMR?

Some of the costs arising during the corona pandemic are partially compensated. New jobs within the health system, industries providing healthcare materials or developing vaccines/medicine partially cover the damages caused to the economy.  

Additional to the healthcare costs, costs due to the impact on the economy arise. According to Maliszewska et al. (2020), financial losses because of the COVID-19 pandemic can be attributed to four categories: 

  1. the direct impact of a reduction in employment (shutdowns of operations), but also labor shortage due to illness of the personnel 
  2. the increase in costs of international transactions 
  3. the sharp drop in travel (caused by travel bans in certain countries) 
  4. the decline in demand for services that require proximity between people (e.g., down periods of restaurants). 

According to a UN (2020) early estimate, the “economic uncertainty it has sparked will likely cost the global economy $1 trillion in 2020”.  

Comparing the costs for both pandemics, AMR does not seem to be as scary as COVID. However, we are only at the beginning. AMR figures are constantly increasing. If O’Neill (2014)’s scenario occurs, we will witness more AMR-caused deaths than deaths from COVID-19, as well as higher costs.  

Antibiotic use promotes the development of resistances 

Antimicrobial resistance is natural; Alexander Fleming mentioned it as early as 1929, soon after discovering penicillin. Most of the antibiotics are derived from natural substances. Penicillin, for instance, is produced by a mold fungus. This is why completely isolated cultures such as the Yanomami in Venezuela, who have never taken antibiotics, can also show resistant bacteria in their gut flora (Lahrtz, 2015). Every contact with an antibiotic has the potential to promote resistance.

Bacteria develop resistance in different ways 

In a typical situation, an antibiotic has an impact on “good” and “bad” bacteria. One bacterium, due to a random mutation, can develop resistance to antibiotic treatment. Suddenly, that resistant bacterium has survived the battle, remains the “king of the castle”, and can use all the space and nutrients to proliferate. 

Different types of resistance are possible (Levy, 1998). The bacteria can  

  • stimulate the production of enzymes, modifying or breaking down (and, therefore, inactivating) the antibiotic 
  • eliminate access ways for antibiotics or develop pumps discharging the antibiotic before it takes effect 
  • change or eliminate the targets of the antibiotics, the molecules they would bind. 

Bacteria spread their ability to resist 

Bacteria spread their ability to resist 

The problem of antibiotic resistance is not only that one bacterium, due to mutation, can withstand an antibiotic treatment. The more dangerous possibility is that it can also transfer this ability to other, potentially more harmful bacteria. How is this transfer achieved? Bacteria can acquire these mutated “resistance genes” through 

  • vertical transfer from mother to daughter cells 
  • the intake of these genes from dead bacteria, which is also possible between different strains (including between “good” and “bad” ones) 
  • plasmids transporting the genes from one bacterium to another (horizontal transfer), which is also possible between strains 
  • viruses transporting the genes.   

Due to this exchange of resistance genes, harmful bacteria can become resistant because they acquire the mutated gene and, therefore, the ability to resist antibiotics from a harmless bacterium.  

problem of antibiotic resistance

Enhanced antibiotic resistance due to COVID-19? 

Just as influenza (Morris et al., 2017), the COVID-19 pandemic is reported to influence the transmission of bacterial infections and the development of antimicrobial resistance. Several reasons and facts argue for this statement. 

  1. Bacterial co-infections are often identified on top of viral respiratory infections. These are then the main reasons for higher morbidity and mortality (Mahmoudi, 2020). Also, COVID-19 weakens the immune system of people and paves the way for secondary infections. This is the reason why, in some cases, COVID-19 patients are given antibiotics prophylactically. Langford and co-workers (2020) published a summary of different studies concerning this topic, and other authors confirm this tendency (Garcia-Vidal et al., 2021Rawson et al., 2020Rodríguez-Baños, 2021Russel et al., 2021). They reported a relatively low incidence of bacterial co-infections of 3.5% (95% CI 0.4-6.7%) and secondary bacterial infections of 14.3% (95% CI 9.6-18.9%). However, high use of antibiotics (70%) could be observed, most of them broad-spectrum antibiotics such as third-generation cephalosporins and fluoroquinolones (Langford et al., 2020). 
  2. Contrary to influenza patients, who get bacterial secondary infections or co-infections in the community, COVID patients are more likely to get these infections in the hospital. There, the risk of “catching” a resistant pathogen is higher.  
  3. This risk increases during a pandemic such as COVID simply because more people spend more time in the hospital. The hospital staff is overloaded; often, hygiene compliance is less than perfect. 
  4. Due to the high number of patients, the determination of bacteria strains is often delayed, and, therefore, doctors more often resort to broad-spectrum antibiotics.  

Antibiotics in animal production contribute to AMR development 

In animal production, antibiotics are not only used for the treatment of diseases but also prophylaxis of the whole herd or growth-promoting purposes. Data collected in the US in 2017 (human) and 2018 (animals) revealed that, in total, nearly 80% of the antibiotics were used in animals. 

Use of antibiotics in animals and humans

Use of antibiotics in animals and humans in the US 2017/18 (according to Benning, 2021

Reduction of antibiotics leads to a decrease in resistances 

A report published by the CDDEP in 2015 showed an earlier example (Dutil, 2010).  When the 3rd generation extended-spectrum cefalosporin (Ceftiofur) was used at the egg stage of broiler chicken farming in Canada, the prevalence of E. coli and Salmonella strains resistant to this antibiotic increased in chicken, but also humans. After discontinuing the antibiotics, the resistance dropped by one-half to one-quarter of the previous year’s value within one year. 

This decrease makes perfect sense. An antibiotic-resistant gene is not worth the organism’s effort if the associated antibiotic is not used, converting the gene into a negative factor for “fitness”. It only costs energy and, in the end, disappearance from the microbiome. 

Antibiotic reduction in animals shows first benefits 

Besides antibiotic stewardship in human medicine (no broad-spectrum antibiotics, targeted use, and only against bacteria rather than viral diseases), reducing antibiotic use in animal production is vital. The European Union has already made strides and banned antibiotics as growth promoters in animal production in 2006. The Netherlands has been leading the way when it comes to a reduction in veterinary prescribed antibiotics. From 2009 to 2018, antibiotic sales decreased by 70% (de Greeff et al., MARAN Report, 2020). First decreases of resistance have already be documented, among which: 

  • no carbapenemase-producing Salmonella in 2019 
  • only 19 ESBL-producing Salmonella isolates were confirmed, mainly from humans 
  • the resistance percentage in commensal E. coli (caecal samples) has halved for most antibiotics, converting into consistently low values during recent years 
  • no E. coli isolates resistant to extended-spectrum cephalosporins were detected in fecal samples from farm animals.  

Preserving the effectiveness of antibiotics is key  

Various feed supplements can support the animals at different stages of their life in order to reduce antibiotic use in animal production. In the long run, this will be a game-changer in ensuring that animal products and the process of animal production itself are not part of the problem. 

Antibiotic reduction has become an increasingly stringent task. In the wake of the COVID-19 pandemic, the world has gained a renewed awareness of the importance of infectious diseases. We saw how fast progress in healthcare could suffer setbacks and we were forced to recognize the need for resilient health systems (Cars, 2021).  

The pandemic can teach us a valuable lesson in this respect. We must realize that it is essential to use antibiotics further as an effective tool to treat harmful diseases. To that end, we must do everything we can to keep this weapon sharp. The first step is to reduce antibiotic use in human health, as well as in livestock production. It will not be an easy way. It is, however, the only effective way in the long run. 



Benning, Reinhild, and By. “Antibiotics: Useless Medicines: Heinrich Böll Stiftung: Brussels Office – European Union.” Heinrich-Böll-Stiftung, September 7, 2021. https://eu.boell.org/en/2021/09/07/antibiotics-useless-medicines.

Bergevoet, R.H.M., Marcel van Asseldonk, Nico Bondt, Peter van Horne, Robert Hoste, Carolien de Lauwere, and Linda Puister-Jansen. “Economics of Antibiotic Usage on Dutch Farms: The Impact of Antibiotic Reduction on Economic Results of Pig and Broiler Farms in the Netherlands.” Research@WUR. Wageningen Economic Research, June 2019. https://research.wur.nl/en/publications/economics-of-antibiotic-usage-on-dutch-farms-the-impact-of-antibi.

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Dutil, Lucie, Rebecca Irwin, Rita Finley, Lai King Ng, Brent Avery, Patrick Boerlin, Anne-Marie Bourgault, et al. “Ceftiofur resistance in Salmonella Enterica serovar Heidelberg from Chicken Meat and Humans, Canada.” Emerging Infectious Diseases 16, no. 1 (2010): 48–54. https://doi.org/10.3201/eid1601.090729.

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Gelband, Hellen, Molly Miller-Petry, Suraj Pant, Sumanth Gandra, Jordan Levinson, Devra Barter, Andrea White, and Ramanan Laxminarayan. “The State of the World’s Antibiotics, 2015.” Center for Disease Dynamics, Economics & Policy (CDDEP), June 8, 2018. https://cddep.org/publications/state_worlds_antibiotics_2015/.

Heckert, R.A., I. Estevez, E. Russek-Cohen, and R. Pettit-Riley. “Effects of Density and Perch Availability on the Immune Status of Broilers.” Poultry Science 81, no. 4 (2002): 451–57. https://doi.org/10.1093/ps/81.4.451.

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Lahrtz, Stephanie. “Resistenzgene auch im Dschungel.” Neue Zürcher Zeitung, April 21, 2015. https://www.nzz.ch/wissenschaft/medizin/resistenzgene-auch-im-dschungel-1.18526784.

Langford, Bradley J., Miranda So, Sumit Raybardhan, Valerie Leung, Duncan Westwood, Derek R. MacFadden, Jean-Paul R. Soucy, and Nick Daneman. “Bacterial Co-Infection and Secondary Infection in Patients with COVID-19: A Living Rapid Review and Meta-Analysis.” Clinical Microbiology and Infection 26, no. 12 (2020): 1622–29. https://doi.org/10.1016/j.cmi.2020.07.016.

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Mahmoudi, Hassan. “Bacterial Co-Infections and Antibiotic Resistance in Patients with COVID-19.” GMS Hyg Infect Control 15, no. Doc35 (2020). https://dx.doi.org/10.3205/dgkh000370

Maliszewska, Maryla, Aaditya Mattoo, and Dominique van der Mensbrugghe. “The Potential Impact of Covid-19 on GDP and Trade: A Preliminary Assessment.” Policy Research Working Papers. World Bank Group, March 2020. https://elibrary.worldbank.org/doi/book/10.1596/1813-9450-9211.

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Broiler production with reduced antibiotics. The essentials

poultry broiler shutterstock 1228945888 small

by Inge Heinzl, Marisabel Caballero, Twan van Gerwe, Ajay Bhoyar – EW Nutrition

Concerns about antibiotic resistance in humans and production animals have prompted a push across the board to reduce antibiotic use, including in livestock rearing. To meet these demands, the industry must keep the pathogenic pressure in production units as low as possible, enabling production with no antibiotics or minimum use of antibiotics.

Broiler production

The 3 essential steps for reducing antibiotics in broiler production

In the following, we discuss experience-based insights and practical advice concerning best practices for broiler meat production with reduced antibiotic use, focusing on the following points:

  • Farm biosecurity
  • Management of the broiler house, including cleaning & disinfection, and environment & litter management
  • Management of the flock, including DOC quality, disease prevention, and nutrition

1. General farm biosecurity

Biosecurity is the foundation for all disease prevention programs (Dewulf et al., 2018). Thus, it is essential in antibiotic reduction scenarios. It includes all measures taken to reduce the risk of introducing and spreading diseases, preventing diseases, and protecting against infectious agents. Its fundament is the knowledge of disease transmission processes.

The application of consistently high biosecurity standards substantially reduces antimicrobial resistance by preventing the introduction of resistance genes into the farm and lowering the need to use antimicrobials (Davies & DWales, 2019).

First of all: everyone must act in concert!

Biosecurity is one of the preconditions for the success of an ABR program, and it is crucial to bring all workers/staff on track through regular training on the best practices and their subsequent rigorous implementation.  The biosecurity plan can only be effective if everyone on the operation follows it – all the time. Farm managers, poultry workers, and other persons entering the facility should adhere to the farm biosecurity measures, 24/24h – 7/7d.

Separation helps to prevent the spread of pathogens

One essential component for biosecurity is implementing a “line of separation” for the farm and each house. It is vital to have a good separation between high and low-risk animals and between areas on the farm that are dirty (general traffic) and clean (internal movements). In this way, it is not only possible to avoid the entrance but also the spread of disease, as potential sources of infection (e.g., wild birds) cannot reach the farm population.

The farm must be well isolated, not allowing the entry or passage of persons who do not work there and animals, including pets.

Inside the farm, the walls of the poultry house form the first line of separation, and the “Two-zone Danish Entry Protocol” constitutes a second line. This system utilizes a bench to divide the anteroom of a poultry house into two sides (outdoor / ‘dirty area’ and indoor / ‘clean area’). At a minimum, footwear should be changed, and hands washed or disinfected when passing over the bench; it is even better when workers have house-specific clothing and hairnets when entering the poultry area.

Safety procedures on the poultry farm

Figure 1: Safety procedures on the poultry farm – the Danish entry method

The room is divided into “dirty” and “clean” zones.

  1. After the entrance from outside, workers/visitors step into a disinfectant boot tray.
  2. They take off their street shoes and leave them on the dirty side of the entrance zone.
  3. Then, they turn from the dirty to the clean side by swinging their legs without touching the floor.
  4. They wash their hands and disinfect them by using the hand.
  5. They must put on an overall, cap, mask, and boots of the poultry house.
  6. Completely clothed, they can enter the poultry house.
  7. When they leave the house, a reversed process must be followed.

Still more needs to be done to prevent the entrance and spread of disease.

Separate materials for each house

For each house, separate materials must be used, keeping a dedicated set of tools and equipment necessary for daily work.

Very important: no materials should be moved from one house to another unless thoroughly disinfected. Crates for bird transport in the case of thinning (partial depopulation of a broiler flock) are an important example.

Practice clean disposal of mortality

First, dead birds’ removal must be frequent (minimum twice a day) as carcasses are a source of infection. The next point is to make sure the route of birds’ disposal is strictly unidirectional, and the buckets or wheelbarrows for the transport of the dead birds do not reenter the poultry house. Finally, the carcasses should remain outside the farm or as far from the buildings as possible until collection, incineration, or composting.

2. Broiler house management

After the general organization on the farm, let’s move on to the poultry houses.

Cleaning and disinfection of the house are the first steps – and check their efficacy!

Cleaning and disinfection are essential components in preventing the persistence and spread of pathogens. Both together aim to decrease microbial numbers on surfaces (and in the air) to a level that will ensure that most -if not all- pathogens and zoonotic agents are eliminated.

Cleaning refers to the physical removal of organic matter and biofilms, so the microorganisms and pathogens are afterward exposed to the disinfectant.

For effective cleaning and disinfection, the all-out/all-in system has proven of value. When birds are collected, all organic material, including feed residues and litter/feces, is removed.

Effective detergents and hot water are used to remove any grease or organic material. Pay special attention to the floors! Also, all surfaces and equipment should be sufficiently cleaned and given final disinfection.

Cleaning is crucial

A study by Luyckx and collaborators (2015) revealed that the mean total aerobic bacterial count on swab samples taken in broiler houses decreases significantly already after cleaning (figure 2). Good cleaning not only strongly reduces microbiological contamination and organic material but also ensures that the subsequent disinfection has a stronger impact on the remaining microorganisms. Consider that all disinfectants, even in high concentrations, are barely effective in the presence of organic material.

reduction of bacteria on surfaces after cleaning and after cleaning and disinfection

Figure 2: % of reduction of bacteria on surfaces after cleaning and after cleaning and disinfection (adapted from Luyckx et al., 2015)

Keep an eye on cleaning & disinfection efficacy

After cleaning and disinfection are complete, it is good practice to check the floors for Total Viable Count (TVC), Salmonella, and E. coli to test the efficacy of the cleaning and disinfection process. Recommended levels of TVC should be less than ten colony forming units per square centimeter (CFU/cm2), and E. coli and Salmonella levels should be undetectable.

When high TVC are found, the cleaning and disinfection procedure must be evaluated, including the products (a rotation is recommended) and their application (e.g., dosage, dilution, water temperature, and exposure time). Also, possible reinfection by vermin or personnel during the downtime must be controlled.


After cleaning and disinfection, a down-time time of 10 days allows disease-causing pathogens to die (UC Davis, 2019).

Cleaning and disinfection of the waterline against biofilm

In the waterlines, the build-up of biofilms can be an issue. Biofilm is a sticky film that can be found inside water lines, regulators, and nipple drinkers. It starts when bacteria attach to a surface and produce a matrix of extracellular polymeric substances (EPS), including proteins and sugars, giving the biofilm the stickiness that traps other bacteria and organic matter. It provides the bacteria with protection from the external environment, and thus they multiply and thrive.

Biofilms not only block the water flow, but they can also include pathogenic bacteria. Thus, the waterline must be regularly cleaned and disinfected, not only between flocks but also within each flock.

waterline in biofilm

Between flocks, an effective waterline cleaning should include:

  • Application of hydrogen peroxide at high concentration, leaving it in the system for 24-48 hours to remove the biofilm from the pipelines)
  • Flush the line to remove the detached biofilm, also activate the nipples with a broom or stick to flush them
  • Immediately before the placement of the new chicks, the water lines should be flushed to have fresh drinking water available to the chicks
  • The water pressure must be adjusted so that a droplet of water is visible at the end of each nipple, and the drinkers are put to the correct height to stimulate water intake and avoid spilling

During the life of the birds, a water disinfectant should be used to prevent biofilm formation, e.g., hydrogen peroxide in weekly applications or the continuous use of chlorine. Also, flushing is a good practice during the whole cycle to make sure that biofilm is removed and the birds count with fresh drinking water.

To a certain extent, biofilm build-up can be prevented by using organic acidifiers in the water, which improves the sanitizers’ effectiveness and reduces bacterial growth in water lines.

Correct ventilation helps to prevent respiratory diseases

To keep broilers healthy, providing optimal ventilation in the poultry house is crucial. CO2 and temperature are the most critical parameters. CO2 should never exceed 2500 ppm and should be monitored continuously, most notably in the early morning before birds increase activity (e.g., eating). Ventilation rates should be adjusted to keep CO2 below this limit. Draught or cold spots resulting in uneven distribution of birds in the house should be avoided, and causes should be investigated and repaired immediately.

Incorrect ventilation often is the reason for respiratory diseases and the need for antibiotic treatment. No matter if natural or power ventilation is used, proper monitoring of the system is indispensable to ensure the well-functioning of the equipment and, therefore, appropriate air quality (Neetzon et al., 2017).

Litter management to keep diseases in check

Effective litter management is another step on the road to keeping the birds healthy. Dryness of litter and ammonia level at bird’s level are two significant key success factors in raising broilers. Dry litter preserves the footpads, so litter material should have a good moisture-absorbing capacity (e.g., chopped straw, wood shaving, rice husks, sunflower husks). When using build-up litter, litter sanitation and treatments need more attention.

Litter treatment (with acidifying or binding substances) and adequate ventilation are the most practical measures to control ammonia and improve littler quality (Malone, 2005). Keep litter temperature at 28 – 30°C (82.4 – 86°F), and use only litter tested or certified to have a TVC <10 CFU/g.

3. Flock management

The basis: healthy, high-quality day-old chicks

To produce good-quality day-old chicks, the parent flocks (PS) must be of good health status. PS should be free from vertically transmitted diseases such as Mycoplasma and Salmonella and be vaccinated/protected against important diseases:

  • Salmonella pullorum/Salmonella Gallinari should be assessed in PS by RPA serology in week 25-30, at least 60 samples per flock.
  • Mycoplasma gallisepticum should be checked by RPA/ELISA serology on a regular basis, preferably at least monthly, with a minimum of 30 samples per flock.

Parent flock vaccination leads to the production of maternal antibodies that help prevent horizontal infection (from the broiler farm environment) in chicks at an early age. This type of prevention is the primary function of some vaccinations, such as against Gumboro disease.

An essential part of the broilers’ life occurs already in the hatchery. Single-stage incubation is recommended, and all floor eggs and dirty nest eggs should be excluded to assure the best day-old chick quality.

Comfortable conditions bring chicks to eat

The brooding phase needs special attention; it is about welcoming the chicks and making them comfortable in the house environment. For this, enough litter needs to be provided, the environment must be managed, and feed and water must be supplied.

At least 24 hours before chick placement, the house and floor temperature are increased to a minimum of 34°C and 28°C, respectively. Proper ventilation and lighting are also essential. These conditions need to be monitored and adjusted after the placement so the chicks feel comfortable and start feed and water consumption. Checking chick behavior is crucial during the first hours after placement.

Upon the placement of the chicks, it is recommended to have pre-starter crumble feed available on top of brooder paper underneath the drinking line. To stimulate early feed and water consumption, gently place the chicks onto that paper. The target is to have 100 % of chicks with crop filled within 48 hours of chick placement.

Reduce the stocking density

chickens feeder In general, high stocking density may restrict bird movement, interfere with airflow, and increase litter moisture and microbial growth, including pathogens, which potentially impairs broiler health, welfare, and performance.

When reducing antibiotics, increase the space per bird by 0.05 ft2/46 cm2 per bird compared to your current conventional program. A lower stocking density helps keep litter moisture at a minimum, which reduces the shedding of cocci oocyst and pathogenic bacteria over the population.

Feed and water access must be granted to all animals at every moment. The number of chickens per feeder or drinker depends on the type of equipment used.

Consistent observation of the flock

To recognize emerging health issues, producers should critically observe the behavior of birds every day. On which points should they focus?

  • First, when entering the house, birds’ behavior and response to the poultry worker should be observed with attention. Note the spread of birds throughout the house.
  • Note birds’ drinking and eating behavior. Feed and water intake should be recorded daily, always at the same hour.
  • The quality of the fresh fecal droppings should be judged. Any changes in the fecal droppings (loss of consistency) can help notice emerging disease and take measures against it.

Especially during and after feed change, attention to changes in the usual feces consistency is necessary.

Vaccination and judicious antibiotic use are crucial

Carefully consider vaccination programs for broilers. Unnecessary vaccinations impact the immune system, possibly resulting in reduced performance and, in some circumstances, make the birds more susceptible to other diseases. Hence, the vaccination program must be diligently attuned (Neetzon et al., 2017).Vaccination and judicious antibiotic use are crucial

  • The disease background of the parent farm as well as the broiler farm where the chicks will be placed are essential factors for the vaccination program
  • If possible, vaccine strains that are the least immunosuppressive should be chosen
  • If coccidiostats are not permitted, an effective vaccination against coccidiosis is required and must be done as early as possible
  • All vaccinations must be given using a standard operating procedure that minimizes bird discomfort and optimizes the vaccine, and always administer vaccines following the advice from the manufacturer

After the vaccination, it is essential to monitor the effects of vaccination stress and take preventive measures to avoid any issues with broiler performance in terms of weight gain and mortality.

Use antibiotics with discernment

As we aim to reduce antibiotics, they should be limited to pure therapeutic use, only if other disease-prevention measures have not been successful, and mortality or disease symptoms make the treatment necessary. Before the treatment, the disease must be diagnosed by a qualified veterinarian. The diagnosis should be preferably followed up by isolation of the disease-causing bacteria, classification, and susceptibility testing before the antibiotics are applied.

Small-spectrum antibiotics that are less likely to cause antimicrobial resistance (AMR) should be preferred. Broad-spectrum antibiotics or antibiotics that are likely to cause AMR can only be used after susceptibility testing has demonstrated resistance to a first-choice antibiotic. The treatment effect must be evaluated by daily monitoring of disease symptoms, mortality, water, feed intake, and body weight gain.

Thinning – things to consider

If thinning (partial depopulation) is practiced, it should be done with the highest bio-security measures. Producers must ensure that the equipment used in the catching process is thoroughly cleaned before entering the house, and bird-catching personnel takes the same measures as farm personnel when entering the farm and the house. These policies will help to minimize the introduction of infectious agents.

Keep the feed withdrawal period for this process as short as possible to avoid flightiness, which can induce skin lesions (some regions catch birds in low light intensities to avoid flightiness). A short feed withdrawal period also prevents over-consumption of feed in a short amount of time, possibly disrupting feed passage in the gut and leading to bacterial imbalance and dysbacteriosis in the remaining birds. After thinning, feed and temperature must be adapted to the lower number of animals.

Provide your birds with high-quality water for drinking

Provide your birds with high-quality water for drinkingWater is the most important nutrient for broilers. It plays an essential role in digestion and metabolism, thermoregulation, and waste elimination.

Several factors affect water quality: temperature, pH, bacteria, hardness, minerals, and total dissolved solids. These parameters should be analyzed at least twice per year. If necessary, corrective actions should be taken, e.g., a filtration to remove minerals, the addition of chlorine for disinfection, or the addition of organic acids to drop the pH.

Before each cycle, the water must be tested for total aerobic + enterobacteria, compared to reference values: Total plate count (TPC) should be < 1000 CFU/ml, and E.coli, Enterobacteriaceae, yeast, and molds at undetectable levels. The section about cleaning and disinfection of the waterline provides insights and practical advice about water sanitation and microbiological analysis.

Nutrition & feeding – a pillar for antibiotic reduction

Nutrition and feeding in ABR broiler production are not only about providing nutrients for growth but also about the effects of the feed on gut health. Gut health is essential for animals’ overall health, welfare, and productivity, even more so in antibiotic reduction scenarios.

Feed should be of the highest quality – in all respects

High feed quality is necessary to provide the animal with the required nutrients and achieve their optimal utilization. Also important is the absence, limitation, or management of harmful substances and pathogens. High quality, therefore, includes:

  • Form and composition of the final feed
  • Nutritional value of the raw materials
  • Management of harmful substances.

From reception and storage of the raw materials to the dispatch of the finished feed, the feed mill management emphasizes their quality assurance system, which is decisive in this connection.

First measure: quality assurance at the feed mill level

The feed mills producing for operations with no or reduced use of antibiotics must have a quality assurance (QA) and/or a good manufacturing program (GMP) in place that guarantees the production of consistently good quality feeds.

Proper raw material management and processing of feeds are necessary to achieve the lowest possible microbial-pathogen load, including:

  • An effective rodent and wild birds control
  • Disinfection of all the vehicles entering the feed mill
  • Proper storage and utilization of raw materials (e.g., first in-first out use, silo management)
  • Periodic thorough cleaning of milling equipment, premises and storage areas, and the monitoring of these activities
  • Standard operating procedure and quality assurance systems that guarantee feed safety and quality
Check the quality of the raw materials and the final feed

Digestion, absorption, and gut health depend on the quality of the feed ingredients. To provide the best preconditions for healthy growth, producers should avoid raw materials of a reduced and/or inconsistent quality. For this purpose, each raw material batch should be analyzed for its specific quality parameters. Quality parameters to consider are:

  • Physical ones, such as color, odor, particle size, and general appearance
  • Chemical ones, such as nutritional composition and specific parameters. For example, grains should be analyzed for mycotoxins and antinutritional factors; fats and oils need to be analyzed for free fatty acids (FFA), unsaturated/saturated (US) ratio, iodine value (IV), but also the peroxide value (PV) as oxidized fats have a lower energy value, and their intake is related to enteric diseases
  • Biological ones, including yeasts, molds, and enterobacteria

Also, the finished feed should be monitored by analyzing every batch concerning composition compared to values in the feed formulation, as well as physical, chemical, and microbiological quality parameters.

Clean storage on the farm prevents feed spoilage

As in the feed mill, keeping the farm facilities clean is of the highest importance. Warehouses, silos, bins, feeders, etc., should be emptied, cleaned, and disinfected after each flock; this avoids the formation of feed aggregates that can lead to mold growth and mycotoxin contamination; also, insects, bacteria, and parasites can remain in those residues.

Green field and factory

Adapt feed formulation and feeding to the feeding phase

The value of phase feeding

Having the correct number of dietary phases to meet animal demands and avoid excess nutrients provides better intestinal health and thus aids production animals in ABR scenarios. The feeding phases should be designed to prevent abrupt changes in nutrition and raw material inclusions, possibly leading to dysbacteriosis.

Feeding for gut health

When feeding broilers in antibiotic reduction scenarios, extra care should be taken when formulating diets. The challenge is to achieve the same performance as conventional management at an optimum cost.

  • Don’t waste nutrients: Improve feed digestibility, and at the same time, reduce the dangers of antinutritional factors coming from different ingredients by using suitable exogenous enzymes.
  • Keep an eye on fiber: Moderate levels of insoluble fibers with adequate structure and composition can be included to promote gizzard development and function. This measure leads to a better modulation of gut motility and feeds passage into the intestine. Additionally, it promotes gut health, resulting in higher nutrient digestibility.
  • Be careful with protein: Excess of undigested protein in the hindgut may lead to the proliferation of Clostridium perfringens; then, subclinical challenges of necrotic enteritis may occur. Moreover, the excess of nitrogen may increase feces moisture content, leading to wet litter. The optimization of the diets based on digestible amino-acid profiles and the use of synthetic amino acids decrease or eliminate the minimum requirements of crude protein, avoiding its excess.
Which feed form?

The feed form depends on the age or feeding phase: starter feeds can be offered as coarse mash, but preferably as crumble or mini-pellets (< 2 mm diameter) and grower and finisher diets as 3 – 4 mm pellets.

When using pelleted diets, quality is also the most crucial criterion. Poor pellet quality and thus the excess of fine particles increase feed passage rate, resulting in poor gizzard development and compromised gut health.

A high-quality pelleted feed can withstand – without much breakage – the handling that occurs after processing, such as transportation, storage, and farm management. Pellet quality can be measured by the Pellet Durability Index (PDI) obtained by simulating the impact and shear forces in a known quantity of feed for a determined amount of time. After this time, the sample is sieved, and the fines are separated, weighed, and compared with the initial sample

The PDI should be measured in the feed mill and compared to a standard. Later, it is also recommended to measure the PDI on the farm, and the producer should take corrective actions if the pellets cannot maintain their quality.

Additionally, it should be known that coarse ground grains stimulate gizzard development and function. So, about 30 % of the feed should consist of particles between 1-1.5mm (post pelleting) in all feeding phases.

Broilers’ selection criteria for feed are form, color, size,
and consistency

Broilers’ selection criteria for feed are form, color, size, and consistency

Broilers’ selection criteria for feed are form, color, size, and consistency. They prefer feed that is easy to pick, such as crumbles or pellets. 

Feed additives can support antibiotic reduction

The feed additive industry provides broiler farms and integrations with various solutions to make production more manageable and efficient.

A healthy start is half the battle

Let’s start with the chicks. The early introduction of beneficial bacteria into the intestinal tract has proven helpful for gut health optimization. This colonization can be achieved with the administration of suitable probiotics preparation at the hatchery. Multi-strain probiotic preparations effectively initiate healthy microbiome development for optimum gut health. For these challenges, support is offered through EW Nutrition’s VENTAR D and ACTIVO LIQUID, phytomolecule-based products for the feed and the waterline, respectively.

Maintain gut health

Gut health is one of the essential preconditions for efficient growth. Only a healthy gut guarantees efficient digestion and absorption of nutrients. Several approaches are recommended to maintain gut health:

  • Promotion of beneficial and reduction of pathogenic gut flora: here, solutions can come in the shape of products based on phy­tomolecules that can be applied with the feed (VENTAR D) or the water (ACTIVO LIQUID)
  • Management of bacterial toxins and mycotoxins: for this topic, products mitigating the toxins’ negative impact on the birds (Product range of MASTERSORB and SOLIS) are offered

Protect your feed

When feed is stored, there is always the risk of bacteria, mold, or yeast overgrowth. Oxidation of feed ingredients, such as fats and oils, reduces their nutritional value. These issues can be prevented by applying:

  • Acidifiers that have antimicrobial effects due to their pH-decreasing effect, which, later on, improves the feed digestibility and stabilizes the GIT flora (ACIDOMIX, FORMYCINE, and PRO-STABIL)
  • Antioxidants preserving ingredients susceptible to oxidation, such as fats and oils (AGRADO, SANTOQUIN, and STABILON)

Improve pellet quality

Moisture retention during the conditioning process influences pellet quality: higher moisture retention entails a higher starch gelatinization resulting in higher digestibility, pellet binding, fewer fines, and a higher PDI. Surfactants (for example, SURF•ACE) are compounds that can reduce the surface tension between the water and the feed, improving moisture absorption during the conditioning process.

Besides that, moist steam in the pelleting process penetrates better and has a higher antimicrobial effect leading to lower production of bacterial and mycotoxins. The possible reduction of the pelleting temperature protects the nutrients.

ABR in broiler production is practicable – by observing some rules

As shown above, antibiotic-reduced broiler production needs many aspects to be considered and a lot of measures to be taken. All of these measures seek to keep animals healthy and avoid antibiotic use. Maintaining gut health is crucial, as only a healthy gut performs well, achieves the optimal utilization of nutrients, and increases growth performance.

Maintaining a successful production unit with no or reduced antibiotic use requires a holistic approach in which best practices must be assured at all levels of the production chain. The feed additive industry provides a broad range of solutions to support animal production through this challenging task. The objective could not be more critical: lowering antibiotic resistance to assure the future of animal and human health.



Davies, Robert, and Andrew Wales. “Antimicrobial Resistance on Farms: A Review Including Biosecurity and the Potential Role of Disinfectants in Resistance Selection.” Comprehensive Reviews in Food Science and Food Safety 18, no. 3 (2019): 753–74. doi.org/10.1111/1541-4337.12438

Dewulf, Jeroen, and Van Filip Immerseel. “General Principles of Biosecurity in Animal Production and Veterinary Medicine.” Essay. In Biosecurity in Animal Production and Veterinary Medicine: From Principles to Practice. Wallingford, Oxfordshire, UK: CABI, 2019. doi.org/10.1079/9781789245684.0063.

Luyckx, K.Y., S. Van Weyenberg, J. Dewulf, L. Herman, J. Zoons, E. Vervaet, M. Heyndrickx, and K. De Reu. “On-Farm Comparisons of Different Cleaning Protocols in Broiler Houses.” Poultry Science 94, no. 8 (2015): 1986–93. doi.org/10.3382/ps/pev143.

Kreis, Anna. “Broiler Feed Form, Particle Size Assists Performance.” Feed Strategy, September 20, 2019. https://www.feedstrategy.com/poultry-nutrition/broiler-feed-form-particle-size-assists-performance/.

Malone, B. “Litter Amendments: Their Role and Use.” University of Delaware – Agriculture & Natural Ressources – Fact Sheets and Publications. University of Delaware, November 2005. https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/litter-amendements/

Neetzon, A. M., Pearson, D., Dorko, N., Bailey, R., Shkarlat, P., Kretschmar-McCluskey, V., Van Lierde, E., Cerrate, S., Swalander, M., Vickery, R., Bruzual, J., Evans, B., Munsch, G., & Janssen, M. (2017, October). Aviagen Brief. Aviagen – Information Library. https://en.aviagen.com/assets/Tech_Center/Broiler_Breeder_Tech_Articles/English/AviagenBrief-ABF-Broiler-EN-17.pdf.

UC Davis Veterinary Medicine. “‘All out All in’ Poultry Management Approach to Disease Control. A Guide for Poultry Owners.” Poultry-UC ANR, March 2019. https://ucanr.edu/sites/poultry/files/301023.pdf


Water Hygiene: The missing ingredient for successful ABF poultry

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by T.J. Gaydos

Water quality is a frequently overlooked part of animal production and it becomes even more important when producing animals in an antibiotic-free (ABF) system. Chickens drink almost twice as much water as they consume feed, and water hygiene is often a second-level priority. Microbes present in water can be primary or secondary pathogens or non-pathogenic. Consuming impure water can add a challenge to the immune system, negatively impacting performance. 

Water hygiene is essential

Water hygiene is essential for achieving antibiotic-free poultry production

Significant resources are spent on the correct nutrients in the diet and the correct additives for bird health. Water quality should be a priority, and a water quality monitoring program is essential for success in an ABF program. All things being equal, animals will perform better if they have access to high-quality water.

The variability of water quality in the grow-out region should determine how many water quality samples are taken. In highly variable areas, water quality should be measured at every season change on enough farms in every region to know if the solutes are changing. If the water quality is good and consistent, monitoring may be reduced significantly. Water quality should be a part of a “problem farm” work up or related to otherwise unexplained poor performance.

Water-soluble additives: Prevent biofilm

The use of water-soluble products is common in ABF production systems and their frequent use may provide a carbon source for bacteria. This, along with warm temperatures and slow water flow in enclosed water systems, makes the perfect environment for biofilm development.

It is important to frequently flush lines, give birds access to fresh water between additives, and sanitize water lines after using a product that can provide nutrients to bacteria in the line. The biofilm is a perfect location to harbor and protect pathogens from acids and mild or under-dosed disinfectants.

Designing a water quality program

Sample collection

The first step to building a water quality program is to understand the challenge on every farm. Correct sample collection is critical to achieving good results. Take a water sample from as close to the well as possible and submit for water quality analysis: pH, hardness, and minerals. This sample should also be submitted for bacterial load: total aerobic plate count (CFU) per mL and total coliforms per mL.

Monitor bacterial load

A drip sample should be collected from the end of the line for bacterial load analysis as well. This will help determine if the bacterial challenge begins at the source or is limited to the house. Additionally, a swab from the inside of the end of the water line should be taken to determine the level of biofilm. The total bacterial count should be less than 1,000 CFU/mL without fecal coliforms in a free-flowing sample, and total bacteria should be less than 10,000 CFU/mL on a biofilm swab.

Monitor water pH

Water should have a pH between 5 and 8. Water with a pH consistently lower than 5 can be damaging to equipment, while a pH over 8 reduces the efficacy of many disinfectants and can have a bitter taste to birds. Hard water can increase scaling of lines and equipment, leading to leaking seals. Scale also provides a matrix for biofilm formation, making cleaning and disinfection more difficult.

Clean and disinfect water lines

Cleaning water lines between flocks is the minimum program for ABF production. Stabilized hydrogen peroxide products are excellent for disinfecting water lines between flocks. The levels needed for proper disinfection of lines are generally too strong for birds, and the lines must be flushed prior to bird placement.

Water lines are often only cleaned in the house; it is important to periodically clean the lines that transport water from the well or water source to the poultry house as this may be a significant reservoir for bacteria. If the well is identified as a source of contamination, it is essential to seek the help of a qualified technician before adding any sanitizing product to a wellhead.

Designing a water quality program poultry farm

Continuous disinfection

Ideally, water should be continuously disinfected with a product that is approved for poultry consumption. One of the best products for continuous disinfection is chlorine dioxide, which is effective at reducing bacteria and also reducing the concentrations of some mineral components. High levels of iron in the water can create a favorable environment for E. coli and other bacteria such as C. perfringens.

In addition to disinfection, chlorine dioxide is an effective treatment to reduce soluble iron levels. High sodium and chloride levels can lead to flushing and promote the growth of some bacteria. If high levels of sodium and chloride are consistent across a grow-out region, it may be possible to decrease the levels in the feed to reduce flushing. If the levels of sodium and chloride are considerably high, reverse osmosis should be considered to improve water quality.

Bottom line: invest in high-quality water

Another effective product is stabilized hydrogen peroxide at an appropriate residual level for bird consumption. There are other options for water line sanitation that can be explored on a case-by-case basis.

There are excellent online resources [link] for poultry water quality. The important message remains, in any case, that investment in high-quality water is a critical step for success in ABF poultry production.



Austin, B.J., J. Payne, S.E. Watkins, M. Daniels, and B.E. Haggard. 2016. How to Collect Your Water Sample and Interpret the Results for the Poultry Analytical Package. Arkansas Water Resources Center, Fayetteville, AR, FS-2017-01: 8 pp.

Scantling, M. and Watkins, S. 2013. Identify Poultry Water System Contamination Challenges. FSA8011. University of Arkansas Division of Agriculture Research and Extension.

Watkins, S. 2008. Water: Identifying and correcting challenges. Avian Advice 10(3):10-15. University of Arkansas Cooperative Extension Service, Fayetteville, AR

Why ABF poultry producers need to invest in pullet rearing

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by T.J. Gaydos

There is no more efficient place to invest than in pullets. Pullets are the future of an integrated company. Successful pullet rearing is simply attention to detail, management, serology, biosecurity, vaccination, and worming. Decisions, both good and bad, made during rearing will follow that company for a year. This is especially true related to the introduction of pathogens such as mycoplasmas, Salmonella, and reoviruses, which are persistent and can be vertically transmitted. The importance of biosecurity in any pullet program cannot be overstated, but it is even more critical in an antibiotic-free (ABF) program.

The 4 pillars of rearing pullets without antibiotics

1. Effective management

It is imperative to properly manage flock uniformity, weight, and frame size. For details on how to manage and feed pullets, it is always advised to use the technical support of the primary breeder company because no one knows their bird better than them. Pullet uniformity is critical to the success of the flock in the breeder house. Uniform and healthy pullets are easier to manage to peak and easier to feed for persistency of lay.

Uniform and consistent feed distribution is crucial to managing pullets: people must monitor feeding on a regular and consistent basis. Simply because the feed disappears before the next feeding does not mean it was distributed in an effective way to all birds. Non-uniform feed distribution is not only bad for uniformity but may train other undesirable behaviors such as race tracking, foraging, and roosting on lines to feed. These behaviors increase the risk for trauma and picking up pathogens in the litter.

Why ABF poultry producers need to invest in pullet rearing

There are multiple stressful transition periods in the life of a pullet. It is advised to spread the stressors apart as much as possible. Do not make major management changes, such as turning birds out, changing their lighting or feed program, all at the same time. The more gradual the transitions are, the easier it will be on the birds, and the more likely they will perform as desired.

2. Heightened biosecurity

It is recommended to have dedicated inside and outside boots for all growers, service technicians, and regular visitors. A divided entrance (i.e., Danish entry) is ideal to further limit the risk of bringing pathogens in from the outside. Rodent and insect control is another important facet of pullet biosecurity and must be closely monitored. Vehicles entering the farm must be consistently cleaned and disinfected.

Managing the risk of pathogen introduction via feed is important and feed hygiene should not be ignored. Visitors are almost always the cause of biosecurity breaks and pullets receive a lot of visitors including vaccination crews that travel between farms with equipment. Ensure that vaccination equipment is properly sanitized between farms and crews always use appropriate personal protective equipment.

3. Focus on intestinal health

One of the most difficult challenges to raising pullets is conferring early and uniform immunity to coccidia. These parasites can be managed successfully with chemicals, ionophores, or vaccine programs, although every program has pros and cons. A fundamental problem with an ionophore program is accidentally feeding ionophores (technically considered antibiotics) to ABF flocks due to logistic errors at the feed mill.

Chemical programs can be very effective at managing Eimeria spp. cycling. Most of the time they work a little too well and birds do not develop adequate immunity; consequently, putting flocks at risk of breaking with Eimeria necatrix after chemicals are removed from the diets. A coccidiosis vaccine program is the most sustainable for rearing pullets.

The relative low density of birds, compared to broilers, and the lower feed consumption and thus lower consumption of water can result in dry litter early. The reduced density can also make it difficult for birds to pick up oocysts early in the coccidiosis cycle. Several techniques may be used to increase the chance of success. Birds can be spray-vaccinated at the hatchery and again when placed in the house. Brooding the birds in a portion (e.g., ¼) of the house for the first 7 to 8 days before turning them out to half house, and then to full house can improve early cycling.


Carefully using built-up litter may improve exposure to beneficial microflora; thereby, improving gut health. Managing intestinal health with the correct non-antibiotic feed additives such as saponins, essential oils, and pre and probiotics can significantly improve pullet health.

A well-designed deworming program is important for bird health and uniformity. It is also essential to help reduce the risk of Blackhead disease, which is caused by Histomonas meleagridis, while its intermediate host is Heterakis gallinarum (cecal worms).

4. Tailored vaccination program

Building a vaccination program for pullets has two critical functions: protect the health of the pullets/breeders and protect the health of the offspring by conferring maternal immunity. The exact constituents of the program depend heavily on regional disease challenges. Matching the program to disease pressure is best accomplished with a combination of a rigorous serology program for hens as well as periodically checking the blood of processing-age broilers.

Serology combined with open communication between the breeder and broiler departments about disease challenges can greatly improve the antigen choices of the vaccination program. Pullet rearing is attention to detail – managing the small details will help the long-term success of the poultry company.

Necrotic Enteritis control for ABF poultry production

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by T.J. Gaydos

Control of Necrotic Enteritis (NE) can be one of the most difficult challenges in a system without the availability of antibiotics. In addition, NE is a costly disease because of mortality and loss of performance. Necrotic enteritis is a multifactorial disease that requires damage to the intestinal mucosa, disruption of the intestinal microflora, and a toxin-producing strain of Clostridium perfringens. If any one of these three items is removed or lessened, the severity or incidence of NE will be reduced.

The 3 must-haves for antibiotic-free necrotic enteritis control in poultry

1. Prevent mucosal damage

Prevent mucosal damage

The most common cause of damage to intestinal mucosa in broilers is excessive cycling of Eimeria maxima. The ubiquitous nature of this parasite in poultry production makes it one of the most important contributors to NE. This species of coccidia is most relevant with respect to NE because its life cycle invades deeper into tissues than other species leading to more damage to the intestinal mucosa.

The life cycle of coccidiosis lasts roughly seven days, with each cycle producing exponentially higher numbers of the parasite. Three consecutive replication cycles are needed to produce immunity. The biology of E. maxima is a significant reason why NE commonly occurs around 18-21 days. However, many other things may damage the intestinal mucosa, including mycotoxins, worms, and rancid fat. Managing all sources of mucosal disruption are critical to preventing and controlling NE.

2. Support the microflora

The importance of the microbiome on health is well known; the ability to modify the microbiome to a more appropriate or healthy status is a more difficult challenge. There is a tremendous volume of research in all species about the impact and importance of intestinal microflora on immunity, health, and disease. The microflora is not static but rather a dynamic community of microorganisms that change with bird age, time of day, composition of the diet, and treatment with antibiotics or other additives. Management of intestinal microflora is a very difficult process because its development and manipulation are not fully understood.

Any significant feed formulation or feed form change is a stress event for intestinal microflora. Feed changes are thus high-risk periods for the development of NE. It is a best practice to avoid feed changes when birds are in the NE risk window. It is important to support the intestinal microflora with either in-feed or in-water products to improve intestinal health during feed changes.


It is important to avoid feed outages. After a feed outage, the disruption to the microflora and the increase in mucus production increases the likelihood of an NE outbreak in the following days. Preemptively adding a water additive to improve intestinal health directly after a feed outage can reduce the risk of NE in the flock.

When managing intestinal microflora: probiotics, prebiotics, plant extracts, enzymes, and organic acids are the most commonly used tools. Each of these product classes interacts with the bird and its flora in a different way and selecting additives with complimentary modes of action is critical to the success of the program. Direct colonizing organisms like Lactobacillus spp. can help to directly change the microflora, providing a more mature and healthier microbiome.

Prebiotics such as mannan- and fructo-oligosaccharides provide a food source for beneficial microorganisms and can interact directly with the immune system of the bird. Plant extracts can have antimicrobial or anti-inflammatory properties that can also modulate the microflora by impacting the growth and metabolism of different species of microorganisms in the intestine.

3. Limit Clostridium perfringens growth

It is not possible to eliminate toxin-producing C. perfringens from the environment. Clostridia are spore-forming microorganisms that are very resistant to disinfectants. However, it is possible to manage the abundance of these microorganisms in a system through proper litter management, sanitation, and disposal of mortality.

A house that has a history of NE should have the litter completely removed and the environment cleaned and disinfected as much as the facility will allow. New clean shavings should be brought into the house at a sufficient depth to limit access to the floor. Several non-antimicrobial feed and water additives have shown promise in reducing numbers of C. perfringens in feces of infected birds. Feed and water additives are an essential tool to reduce the impact of NE.

Limit Clostridium perfringens growth

Conclusion: the more you prevent, the less you have to treat

Even with the best management practices, outbreaks of NE will happen. In order to successfully treat a flock with NE, it is critical to catch the mortality early. Once a flock is experiencing high mortality from NE, it is very difficult to treat because the sickest birds will not be drinking enough water to receive a significant amount of water additives. Treating or managing an outbreak is as much art as science, but it is a combination of reducing the inciting causes.

Manage microflora and clostridial growth with organic acids, copper sulfate, phytogenics, or probiotics. Reduce coccidiosis cycling with amprolium, saponins, or other phytogenics. With excellent husbandry, the impact of NE can be reduced drastically even without using antibiotics. Managing NE incidence in poultry is a mixture of animal husbandry, managing coccidiosis cycling, feed and water additive selection, and high-quality nutrition.


Nutrition and feeding in ABF poultry production

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by T.J. Gaydos

Management practices and feed additive selection are often discussed when working in antibiotic-free (ABF) poultry production. Nutrition is another critical component of any agricultural animal system. Working with a qualified nutritionist will help ensure that the diet is correctly formulated with high-quality ingredients.

Chick Feed 

5 nutrition tips for antibiotic-free poultry production

1. Consider feed form and delivery

Feed form and delivery are nearly as important as the nutrient content of the formulation. If feed form or handling is improper and feed separates, is improperly mixed, or oxidized, the birds will not appreciate the effort that went to develop a balanced diet. A durable pellet or crumble is important to allow all birds to have equal access to a nutritionally complete diet with every bite.

Additionally, if the finished feed or individual ingredients are not stored properly, they may not have the same value that is attributed to them in the formulation process. Other than correct nutrient formulation, three parts of the diet that should be considered are feed additives, mycotoxin contamination, and lipid oxidation.

2. Prevent oxidative stress

The impact of oxidative stress on the intestinal mucosa, immune system, and performance is well-documented across species. Oxidized fat sources reduce the available energy, but equally significant to bird health is the reduction in vitamin availability, resulting in increased oxidative stress for the animal. Protecting the sources of fat and the finished feed is important to spare fat-soluble vitamins, specifically vitamin E.

Oxidized fat can also irritate the intestinal mucosa leading to decreased absorption of nutrients. The process of breaking down macromolecules during digestion and converting them to forms useful for further metabolism is a significant contributor to oxidative stress. The immune system is also a great contributor to oxidative stress. Immune cells use reactive oxygen species to kill pathogens that are phagocytosed.

A large portion of the immune system is located in the GI tract in order to protect the animal from pathogens crossing from the gut into the animal. In addition to being a contributor to oxidative stress, the immune system can be negatively impacted by oxidized feed (Liang et al., 2015). The combination of metabolic and immune activity in the intestines puts it at a high risk of damage from oxidative stress. It is vital to protect fat sources with synthetic or natural antioxidants; reducing the incoming stress from oxidized fat should be a priority to improve poultry health.

Chicken Feed

3. Mitigate mycotoxin risks

Another risk to bird health and mucosal integrity is mycotoxins. Diets containing mycotoxins may damage the mucosa of the GI tract directly or may damage other organs leading to significant health challenges and decreases in performance. Some mycotoxins or compounds created by fungi can disrupt the intestinal microflora by acting on bacterial cells, as many fungal metabolites are antimicrobial.

The best approach to managing mycotoxins is eliminating them from the system by purchasing high-quality grain and storing it appropriately. It is impossible to completely eliminate all risks of receiving ingredients contaminated with mycotoxins. An internal program should be developed to test the incoming ingredients and finished feed regularly for mycotoxins.

Knowing the challenging ingredient sources may help reduce the risk to highly susceptible birds like Breeders or chicks through dilution in formulation or the addition of toxin binders and/or enzymes. Several toxins may be found in a feed stuff and many of the mycotoxins are synergistic in their deleterious effects (Murugesan et al., 2015). Different binders have varying affinity for different mycotoxins; closely examining the product literature can help to choose the correct product to mitigate risk.

4. Choose optimal additives

Choosing the correct feed additive program for intestinal health, food safety, and growth performance depends on the specific challenges in the complex. When selecting a feed additive that is not FDA approved, it is important to base the decision as much as possible on scientific evidence through peer-reviewed research.

In addition to published data, internal testing within the production system is also helpful to ensure the product matches the local challenge. In a market saturated with “natural” products, it is essential to find a supplier that is trustworthy and is engaged in the success of the complex and health of the birds, not only in selling products. A partnership will be much more successful in the long term than only a buy/sell arrangement.

5. Manage expectations

When considering removing antibiotics from a program, the temptation is to expect natural products to completely replace the efficacy of antibiotics. This is an unreasonable expectation. The success of a transition to ABF production relies on modifying management practices as well. The vast majority of program success is related to attention to the details of husbandry, biosecurity, and sanitation. The remaining opportunity to improve health rests on the additive program.


Liang, Fangfang, Shouqun Jiang, Yi Mo, Guilian Zhou, and Lin Yang. “Consumption of Oxidized Soybean Oil Increased Intestinal Oxidative Stress and Affected Intestinal Immune Variables in Yellow-Feathered Broilers.” Asian-Australasian Journal of Animal Sciences 28, no. 8 (2015): 1194–1201. https://doi.org/10.5713/ajas.14.0924.

Murugesan, G.R., D.R. Ledoux, K. Naehrer, F. Berthiller, T.J. Applegate, B. Grenier, T.D. Phillips, and G. Schatzmayr. “Prevalence and Effects of Mycotoxins on Poultry Health and Performance, and Recent Development in Mycotoxin Counteracting Strategies.” Poultry Science 94, no. 6 (2015): 1298–1315. https://doi.org/10.3382/ps/pev075.


What poultry producers need to know about coccidiosis control

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by Martin Roa, Madalina Diaconu, and Ajay Awati, EW Nutrition Technical Team


Coccidiosis is one of the most devastating enteric challenge in the poultry industry costing over over 14 billion US$ per year (Blake et al., 2020). In the early days of  intensive poultry production, outbreaks of Eimeria tenella, were most destructive. Eimeria tenella is a coccidia species that causes severe haemorrhages and hypovolemic shock, leading to a fatal outcome for the affected bird. 

Poultry producers need to control the performance and welfare issues caused by subclinical coccidiosisPoultry producers need to control the performance and welfare issues caused by subclinical coccidiosis

Understanding and managing coccidiosis in poultry

However, today, subclinical coccidiosis accounts for even more of production losses due to intestinal cells injuries: lower body weights, higher feed conversion rates, lack of flock uniformity, failures on skin pigmentation and, at the end mortality. Variation in the supply and quality of animal feed exacerbates the issue and compromises farm profitability even more. To tackle this challenge, we need to understand the basics of coccidiosis control in poultry and what options producers have to manage coccidiosis risks.

From Eimeria infection to disease

Coccidiosis is a disease caused by protozoan parasites, mainly of the genus Eimeria, that are located in the small and large intestines. Being very resistant and highly contagious, these protozoa are easily transmitted by various routes (via feed, litter, water, soil, material, insects, and wild animals).

Coccidia are present in all livestock species. However, the infection is particularly severe in poultry. The health consequences can be significant: loss of appetite, reduction in feed intake, increased FCR, enteritis, hemorrhagic diarrhea, and mortality. The most common species of Eimeria in broilers are: E. acervulina, E. mitis, E. maxima, E. brunetti, E. necatrix, E. praecox, and E. tenella. They are widely found in broiler productions across the globe (McDougall & Reid, 1991).

Sporulated oocyst of Eimeria maxima and E. Acervulina Figure 1: Sporulated oocyst of Eimeria maxima and E. Acervulina (40 x)

The pathogenesis of infection varies from mild to severe and is largely dependent on the magnitude of infection. Coccidiosis outbreaks are related to multiple factors that, together, promote a severe infestation in the farm.

Within poultry, the highest economic impact is in broilers, where the most common species of Eimeria are E. acervulina, E. maxima, E. tenella and E. necatrix, which all show high virulence. However, pathogenicity is influenced by host genetics, nutritional factors, concurrent diseases, age of the host and the particular species of the Eimeria (Conway & McKenzie, 2007).

Interaction of factors that promote coccidia outbreaksFigure 2: Interaction of factors that promote coccidia outbreaks

The Eimeria infection starts with the ingestion of protozoa that are at a sporulated stage. Once inside the gut, the protozoa liberate the sporozoites. This infective form can get into enterocytes and then begin a massive reproduction, killing thousands of intestinal cells. (Olabode et al., 2020; Shivaramaiah et al., 2014)

Eimeria spp. life cycleFigure 3: Eimeria spp. life cycle

The reproduction potential depends on the coccidia species. E. acervulina, E. mitis and E. praecox have the highest reproduction rate. This characteristic is closely related to their short life cycle.

In broilers, coccidiosis usually occurs after 21 days of age. The infection spreads gradually from day 1 already, depending on species of Eimeria and their virulence. A typical progression of coccidiosis in broilers is shown in Figure 4.Typical development of a coccidia infection in relation to broiler feed phasesFigure 4: Typical development of a coccidia infection in relation to broiler feed phases

Coccidiosis control in poultry: Strategy guidelines

The intrinsic characteristics of coccidiosis makes this parasite unique and many times frustrating to control. Resistance to available coccidiostats makes this task even harder.  Good farm management, litter hygiene, and the use of control coccidiosis programs such as shuttle and rotation are functional measures to prevent clinical coccidiosis. Successful control strategies specifically recognize the importance of monitoring, use anticoccidial drugs wisely, and include vaccines where applicable.


The first step is to establish a strict monitoring program in all stages of production, including the feed mill. It is important to verify that therapeutics are included in the feed in an adequate form and quantity, and that the follow-up in the field takes place.

Field monitoring should be frequent and in line with the operation’s coccidiosis management program. Field monitoring is a complementary work that collates clinical, necropsy, and faeces findings to closely track the disease situation.

Coccidiosis control in poultry operations needs to include rigorous monitoringCoccidiosis control in poultry operations needs to include rigorous monitoring

Anticoccidial drugs

Since the middle of the 20th century, chemotherapeutic agents have offered the best way to control coccidia. However, unbridled use of anti-coccidial drugs and the emergence of the new resistant field strains of coccidia have made it increasingly challenging to control coccidiosis with commonly available coccidiostat drugs.

The coccidiostats have been classified in two groups: ionophores, molecules obtained from microbiological fermentation, and chemicals, synthetic compounds. The mode of action of ionophores is to interfere with the membrane ion exchange, killing the extracellular stages (sporozoites and or merozoites) as they expend energy to maintain the osmotic balance. Chemical compounds can have an anticoccidial effect even on extracellular and intracellular stages (Sumano López & Gutiérrez Olvera, 2005).

However, resistance development is limiting their effectiveness, and certain compounds cannot be used in older birds or in hot environments. Moreover, government regulations often include anti-coccidial drugs in bans on antibiotics use. This does not mean that these drugs are not crucial to controlling this disease, but it is important to use alternative tools: they help make a coccidiosis control program not only less dependent on anticoccidial drugs but also more robust.


There are two commercial kinds of coccidia vaccines; the first one uses natural strains. These Eimeria are selected from field outbreaks, show a medium pathogenicity, and allow for a controlled replication of a coccidia infection. The second kind of vaccines include attenuated strains; these are precocious strains and birds usually show low or no post-vaccinal reactions.

The management of coccidia vaccines is the principal challenge for using this tool to control coccidia. Special vaccination training is required at the hatchery, which then needs a follow-up on the farm. In the field, this follow-up and the alignment of all the protocols has proven challenging for many producers.

Managing coccidiosis in poultry: Next steps

The limitations chemotherapy and vaccines have led to a surge in the quest for effective  natural solutions. Recent research into plant-derived phytochemicals shows that these compounds have properties that make them an interesting tool against coccidiosis (cf. Cobaxin-Cárdenas, 2018). Knowledge, research, and technological developments are now ready to offer solutions that can be an effective part of coccidia control programs. These natural solutions create opportunities to make poultry production more sustainable by reducing dependency on harmful drugs.


Bafundo, K.W., L. Gomez, B. Lumpkins, G.F. Mathis, J.L. McNaughton, and I. Duerr. “Concurrent Use of Saponins and Live Coccidiosis Vaccines: The Influence of a Quillaja and Yucca Combination on Anticoccidial Effects and Performance Results of Coccidia-Vaccinated Broilers.” Poultry Science 100, no. 3 (2021): 100905. https://doi.org/10.1016/j.psj.2020.12.010.

Blake, Damer P., Jolene Knox, Ben Dehaeck, Ben Huntington, Thilak Rathinam, Venu Ravipati, Simeon Ayoade, et al. “Re-Calculating the Cost of Coccidiosis in Chickens.” Veterinary Research 51, no. 1 (September 14, 2020). https://doi.org/10.1186/s13567-020-00837-2.

Cobaxin-Cárdenas, Mayra E. “Natural Compounds as an Alternative to Control Farm Diseases: Avian Coccidiosis.” Farm Animals Diseases, Recent Omic Trends and New Strategies of Treatment, March 21, 2018. https://doi.org/10.5772/intechopen.72638.

Conway, Donal P., and M. Elizabeth McKenzie. Poultry Coccidiosis: Diagnostic and Testing Procedures. Ames, IA, IA: Blackwell Publishing, 2007.

McDougall, L. R., and W. M. Reid. “Coccidiosis.” Chapter. In Diseases of Poultry, edited by B. W. Calnek, H. W. Yoder, W. M. Reid, C. W. Beard, and H. J. Barnes. Ames, IA: Iowa State University Press, 1991.

Olabode, Victoria Bose, Dashe Yakubu Gunya, Umaru Mada Alsea, Tobias Peter Pwajok Choji, and Israel Joshua Barde. 2020. “Histopathological Lesions of Coccidiosis Natural Infestation in Chickens”. Asian Journal of Research in Animal and Veterinary Sciences 5 (2), 41-45. https://www.journalajravs.com/index.php/AJRAVS/article/view/30090.

Shivaramaiah, Chaitanya, John R. Barta, Xochitl Hernandez-Velasco, Guillermo Téllez, and Billy M. Hargis. “Coccidiosis: Recent Advancements in the Immunobiology of Eimeria Species, Preventive Measures, and the Importance of Vaccination as a Control Tool against These Apicomplexan Parasites.” Veterinary Medicine: Research and Reports 2014, no. 5 (April 28, 2014): 23–34. https://doi.org/10.2147/vmrr.s57839.

Sumano López, Héctor, and Gutiérrez Olvera Lilia. Farmacología Clínica En Aves Comerciales. México: UNAM, Departamento de Fisiología y Farmacología, 2005.

Hatchery management in ABR production

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by T.J. Gaydos

Producing high-quality chicks is critical to the success of any broiler program, but it is even more important in an antibiotic-free (ABF) program. The hatchery is the perfect environment for the incubation of eggs and, consequently, bacteria and mold. This makes hatchery sanitation a very high priority in ABF production systems because of the inability to use antibiotics in the hatchery or later in production.

Chick quality can be divided into two categories:

  • microbiologic
  • chick vitality

The reality is many of the processes that impact these two categories are often intertwined but can be generally separated into

  • sanitation practices
  • setting/hatching practices

It is not helpful to set specific objective benchmarks for an individual hatchery without understanding its specific challenges. The hatchery manager must realize that the end product is a healthy, robust chick; therefore, benchmarks and numerical goals for the individual hatchery, breed, and flock age need to be established.

There are a host of measurements that can be performed and data that can be collected; however, it only makes sense to collect only information that will be used to make decisions. It is easy to over-collect and under-utilize data.

Hatchery sanitation

Bacterial contamination

Hatchery sanitation starts at the breeder farm. Eggs are a significant source of contamination in the hatchery; consequently, floor eggs should not be brought to the hatchery. If they must be hatched for egg flow needs, it is essential to at least segregate them from the regular egg flow throughout the process. It is imperative to send a clean egg pack to the hatchery (transport and store the eggs at proper temperatures and humidity). Once the eggs are at the hatchery, the focus is on proper storage, incubation, and hatching. 

Monitoring sanitation

The risk of multiplying bacteria in the hatchery is high. Hatchery equipment can be difficult to clean, there are sufficient nutrients to support microbial growth, and the environment is perfect for incubation. Developing a program to monitor the cleanliness of the hatchery is a critical step in managing sanitation. The whole hatchery must be regularly cleaned and disinfected, and the most effort should be spent on chick contact surfaces.

Egg flats must be clean and dry before returning to the breeder farm. Hatcher baskets must be clean and dry before eggs are transferred. The tray wash machine should use a detergent and disinfectant to remove and sanitize the trays (the water temperature should be 140oF). A disinfectant with residual efficacy should be used after the tray wash. Too low of a temperature will encourage bacterial growth, and too high a temperature can damage the baskets.

When using an in ovo vaccination system, it is essential to clean and disinfect the machine after every use and prepare it for the next transfer. Chick belts, counters, chick baskets, hatchers, and setters are all areas that can harbor pathogens. Wet areas are also at risk for harboring disease: wet bulb thermometers, humidification equipment, and tray washers. All these areas should be regularly checked for cleanliness by traditional microbiology or rapid ATP testing.

It is important to monitor the hatchery air quality on a regular basis to ensure the level of bacteria and fungi is not too high. This is most effectively accomplished by placing air plates in key locations for air movement such as clean hatchers and setters and their respective halls, and plenums. The areas where vaccines are stored, mixed, and prepared should be surgical suite clean. 

Hatching practices

Chick vitality

A high-quality, active chick is one of the keys to program success. The actual profile used to hatch that bird is a mixture of breeder flock profile, hatchery equipment, climate, and experience. When evaluating a hatchery and a hatching program, it is best to start at the endpoint and work backward.

Managing chick comfort in the holding room is vital to set the chicks up for success on the farm. The chicks will tell you if they are too hot or too cold and if they have too much or too little airflow. This is determined by experience and monitoring behavior.

Tracking chick rectal temperatures is a useful way to check comfort. Remember that a small animal can change their body temperature from ideal to hyper- or hypothermic extremely quickly. On average, 103.5oF is a good benchmark for chick internal temperature. Moving backward through the process, evaluate the vaccine spray cabinet to ensure chicks are getting the proper vaccines at the proper rate.

The next critical opportunity to monitor chick vitality is when chicks are being separated from hatch debris. The volume of chicks passing through the site allows for rapid evaluation of the flock. In this area, it is important to check for open navels, strings, red hocks, green chicks, dirty chicks, and general appearance and behavior.

Hatch debris

The egg should be pipped and broken almost exactly in half. The debris should have minimal meconium, yolk stains, and should not smell bad. Excess meconium is an indication that the hatch window is prolonged, and the chicks spent too much time in the machine before pull.

When eggshells are crushed in one’s hand they should break, but the membrane should remain intact. If the membrane also breaks, it is a sign that the chicks were potentially overheated, incubated too long, or humidity was too low. 

Chick yield

One of the most useful measures of the setting process is chick yield, which is the weight of the chick at hatch compared to the weight of the egg set. Chicks with a low yield were set with a high temperature or low humidity or were hatched for a long time before being removed from the hatcher. Chicks with a high chick yield are a result of the opposite: low temperature and high humidity incubation or did not spend enough time in the hatcher post-hatch. The ideal chick yield depends on the breed of chicken and the individual hatchery, but 67-68 % yield is a good benchmark.


Analyzing hatch debris is a crucial tool for understanding setting and hatching efficiencies. Embryo mortality is variable but tends to follow a consistent pattern. The majority of embryo mortality is early (1-7 days), with little mortality in the middle (8-14 days), and the second increase in embryo mortality occurring from 15-18 days. Results should be recorded, and a standard developed for the hatchery. Deviations from this standard should be investigated.

When aiming to improve the data collection process, focus on building a program that prioritizes the most useful information. Breakouts and chick yields are two of the most meaningful tests to modify the hatching process. Sanitation checks and monitoring of disinfectant levels at critical sanitation steps are valuable to improve hatchery quality. When all the pieces come together, high quality egg pack, sanitation, and excellent hatchery management, the result is a high-quality chick ready to succeed on the farm.