Probiotics for Chickens: Benefits, Types & Application (2024)

By Chicken Fans Editorial Team
Co-Authored & Medically Reviewed by Dr. A. Ibrar, DVM, Poultry Nutritionist
University of Veterinary and Animal Sciences, IUB, Selçuk Üniversitesi

what are probiotics | when to use | health benefits | types | chicks | how to give | vs antibiotics | vs prebiotics | criteria | growth performance | egg laying | gut health | immune system | microbiota | homemade | risks

Probiotics are tiny, helpful bacteria and yeasts living in the chicken’s gut. Billions of microbes keep the droppings smooth and boost the immune system.

Giving probiotic supplements boosts the natural supply of beneficial bacteria. They fight off harmful bacteria and improve egg laying. Say goodbye to antibiotics and hello to the power of probiotics for chickens.

In this article, we work with vets to give an overview of probiotics on the market, when to give them and how you can put them to good use. We go in depth on the current findings of poultry research so you can apply them on your backyard flock and boost egg laying, growth, the immune system, and the gut microbiota.

Here are the main takeaways:

  • control diarrhea, counteracts antibiotics, helps with illness and stress
  • boosts growth, egg-laying, feed ratio, gut health, digestion
  • improves chick survival rate
  • legal, all-natural replacement for antibiotics
  • categories are lactic acid bacteria, brewer’s yeast, bacillus, and Aspergillus
  • prefer bacillus to boost egg laying
  • use fermented apple cider as a homemade probiotic

What are Probiotics for Chickens?

Probiotics for chickens are natural supplements with live microorganisms found in the chicken’s digestive system. They promote a healthy gut, boost the immune system and egg laying, and prevent viral and bacterial diseases. Poultry probiotics include lactic acid bacteria, brewer’s yeast, bacillus, and Aspergillus.

These are not just empty claims. You can really bring your chickens to their full potential with the power of probiotics. The list of health benefits is enormous.

two hens eating yoghurt

Chickens can get probiotics by eating food based on live cultures, like yogurt, cheese, sauerkraut, apple cider vinegar, cheese, and sour cream. However, there are many cost-effective supplements available that contain a multitude of microorganisms proven to be highly effective for chickens.

When to Use Probiotic Supplements for Chickens

Probiotics for chickens are especially useful in the following cases:

  • for chicks after hatching
  • after a course of antibiotics
  • to control diarrhea and digestive issues
  • to control dirty, poopy butts in adult chickens
  • during peak production of laying hens
  • to increase the growth and fertility of roosters
  • to prevent bacterial diseases like E. coli or salmonella
  • to improve feed efficiency and improve overall growth
  • during times of stress such as molting, moving, or heat stress

That said, there is no specific indication for probiotics. Supplements can always safely be added to a chicken’s diet at any age, regardless of the breed.

  • For ill chickens, probiotics counteract the causative agent and lead to better health and swift recovery.
  • In healthy chickens, probiotics enhance growth performance with better digestion (improved gut microbiota), absorption (enhanced villus height, better gut morphology), and protection (boosted immunity).

Health Benefits of Probiotics for Chickens

The following table gives an overview of all the health benefits of probiotics for chickens.

improves growth performanceaccelerates the overall growth
improves feed ratioless feed to gain the same amount of weight
improves egg-layingenhances laying performance (chickens lay more eggs)
improves egg quality and size
boost the immune systemincreases survival rates for chicks
prevents Salmonella infections
prevents Infectious Bronchitis, Newcastle Disease, and Marek’s disease
prevents immunosuppressive diseases
improves gut healthused to treat diarrhea
reduces bad bacteria in the guts
reduces ammonia in the droppings
lower cholesterol levels
has an antiparasitic effectreduces coccidian parasites that cause coccidiosis
improves digestion and nutrient absorptionsupplies digestible proteins and vitamins
lactic acid facilitates nutrient absorption
improves vitamin synthesis and absorption

For the time being, poultry scientists don’t fully understand how probiotics work, but many health benefits come from two well-known mechanisms:

  • Competitive Exclusion: good probiotic bacteria take place and resources away from bad bacteria and pathogens in the chicken’s gut. They occupy the gut’s adhesive receptors that malicious microorganisms need to attach and grow.
  • Bacterial Antagonism: the interaction between bacteria where good bacteria reduce the growth or activity of bad bacteria. Probiotics produce antimicrobial substances, compete for nutrients, and modulate the chicken’s immune system.

However, there are several types of probiotics. The specific health effects depend on the various strains. That’s why many commercial feed supplements use multi-strain probiotics.

Types of Probiotic Poultry Supplements

Probiotics are a modern class of feed additives and supplements based on bacterial, fungal, and yeast cultures.

There are four big categories of probiotics used in poultry supplements:

  • Lactic Acid Bacteria: these bacteria turn sugar into lactic acid. They are the bacteria in fermentation to make food like yogurt and cheese. They can be found in milk, plant, and meat products.
  • Non-Lactic Bacteria: some microbes don’t produce lactic acid but are still beneficial. Bacteria like Bacillus are used in soya-based natto fermentation (natto is a Japanese dish made from fermented soybeans)
  • Fungi: molds like Aspergillus are used to produce fermented foods like soy sauce, miso, and sake, but they do not produce lactic acid
  • Brewer’s Yeast: Saccharomyces is a yeast culture that is recently discovered to be beneficial for chicks. It’s commonly used to produce fermented foods such as bread, beer, and wine.

Here is an overview of the different strains of probiotics used in poultry:

Probiotics FamilyStrains used in Poultry
Lactic Acid BacteriaLactobacillus, Streptococcus, Bifidobacterium, Lactococcus,
Enterococcus, Pediococcus
Non-Lactic BacteriaBacillus
Fungus / MoldAspergillus
Brewer’s YeastSaccharomyces

These strains are typically printed on the supplement’s label. Most supplements contain a mix of different strains in various amounts.

Probiotics for Chicks

When chicks hatch, their stomach is still sterile, and the microflora in the guts is still developing and maturing. When chicks grow up, they acquire microbes from their environment when they are approximately 7 to 11 weeks old.

chicks in a brooder on a feeder

This microflora colonization of the intestine is a slow process. During these first weeks, chicks interact with their mother and are very susceptible to bad germs. These bad germs spread more easily than good bacteria. Therefore, using probiotics in this early life stage is extremely beneficial.

This is especially true for chickens that live in stressful environments, like broiler chicks.

How to Give Chickens Probiotics

Probiotic supplements for chickens are sold as dry powders that can either be added to the feed or the drinking water. The dosage and usage are expressed in colony-forming units (CFU).

As all commercial products are a different mix of strains, it’s important to closely follow the instructions that come with the specific product at hand. Even a small scoop of probiotic powder contains billions of organisms.

Probiotics as a Replacement for Antibiotics in Poultry

Antibiotic supplementation has always been a standard practice in poultry farming to prevent diseases. They are also popular as AGP (antibiotic growth promoting agent) to boost growth performance.

However, the European Union and several other regions have already banned the use of antibiotics in chickens. And for a good reason.

There are several problems with antibiotics for chickens:

  • antibiotics also kill the beneficial bacteria
  • antibiotic residues can be found in the eggs
  • antibiotic residues can be found in the meat
  • antibiotic resistance arises

By giving chickens so many antibiotics regularly, the bacteria change and learn to resist these antibiotics. This poses a huge human health risk. Furthermore, antibiotic residues in chicken eggs and meat can also seriously harm human health.

antibiotics chickens

Antibiotics will be phased out sooner rather than later. Probiotics are safe and less expensive, with no negative side effects. They also don’t leave any residues in the eggs or meat.

Probiotics are far more beneficial than antibiotics for growth, enhanced immunity, enriched microflora, improved gut health, stronger bones, and thicker eggshells.

This all makes probiotics a much better choice than antibiotics.

Difference Between Probiotics vs. Prebiotics

Probiotics are supplements or foods with live bacteria that improve the gut’s microflora. Prebiotics is fibrous feed that these (probiotic) bacteria digest. For example, yogurt is a probiotic, rich in beneficial bacteria, whereas bananas are prebiotics with sugars consumed by these bacteria to produce lactic acid.

Simply put, probiotics are the live organisms themselves. Prebiotics is sugary food that bacteria can eat.

Criteria for a Perfect Probiotic Supplement

There are many strains of bacteria that can be used as probiotics. Not all commercially available products are created equal.

For a specific product to be useful as a probiotic for chickens, it needs to:

  • be able to remove harmful germs
  • include a substantial number of live bacteria
  • include strains that are useful for chickens
  • withstand the chicken’s intestinal pH-levels
  • recently gathered (bacteria have limited shelf life)
  • have a stable manufacturing process

The effect of a probiotic is also dependent on the presence/absence of antibiotic resistance that might be present in the flock.

Probiotics for Better Growth Performance

With antibiotic growth promotor (AGP) drugs being eliminated in chicken feed, probiotics are actively studied for their ability to increase growth performance in commercial chicken production.

Following probiotics have a positive effect on growth performance:

  • Bacillus: Bacillus licheniformis, Bacillus subtilis)
  • Lactobacilli: Lactobacillus bulgaricus, Lactobacillus acidophilus
  • Fungi: Aspergillus oryzae
  • Yeast: Saccharomyces cerevisiae

Antibiotic Growth Promoters vs. Probiotics

AGPs function by suppressing the generation and elimination of catabolic agents by intestinal immune cytokines, resulting in decreased intestinal microbiota. Probiotics, on the other hand, stimulate growth by altering the gut environment and improving gut barrier integrity through the fortifying of beneficial intestinal microorganisms, selective exclusion of pathogens, and immune system activation (for example, galactosidase, amylase, and others). This aids in nutrition absorption and increases animal development performance.

Although drugs and probiotics have different ways of working, both have the potential to increase growth performance. Body weight gain (BWG) improvement is often connected with higher average daily feed intake (ADFI) and better feed conversion ratio (FCR).


According to research, both Bacillus licheniformis and Bacillus subtilis, as probiotics, enhance body weight gain, feed conversion ratio, and overall production efficiency of chicken birds. 

A study was conducted in china by feeding Bacillus coagulans to salmonella enteritidis-challenged broilers. The body weight gain and the feed conversion ratio of birds were enhanced compared to those not supplemented with Bacillus coagulans in the second and third weeks of the study.


Both L. bulgaricus and L. acidophilus improve broiler chick performance. In tests with broiler chicks, L. bulga­ricus supports growth much better than L. acidophilus. In these tests, bacteria are grown on skimmed milk at 37°C for 48 hours. There are several studies to support the growth benefits of Lactobacillus bulgaricus.

Aspergillus oryzae Fungi

Several studies indicate that A. oryzae in broiler chick diets increases body weight growth and feed intake. A. oryzae also decreases ammonia gas production and lowers cholesterol in chickens.

Saccharomyces Yeast

Recent discoveries show that the yeast S. cerevisiae enhances growth and carcass weight. This is the result of the changing gastrointestinal flora and the boost in nutrient uptake.

In one study, body weight gains are 4.25 % larger, and feed conversion ratios are 2.8% lower than chickens on a normal diet.

Probiotics for Egg Laying Hens

Adding probiotics to laying hen diets increases laying productivity by boosting daily feed consumption, improving nitrogen and calcium absorption, and lowering intestine length.

Probiotics have been claimed to enhance the efficiency of gastrointestinal fermentation and the generation of short-chain fatty acids, which nourish intestinal epithelial cells and hence boost mineral and nutrient absorption.

Broody hen inside the nesting box

Selenium and Bacillus subtilis

Egg quality involves various criteria, such as shell weight, egg white, and yolk quality. In one study, a selenium-enriched probiotic was offered to laying hens in a study to determine its effect on egg quality, the selenium content of the egg, and the overall laying performance of hens. Selenium supplementation enhanced the laying ratio and egg weight.

This selenium-based probiotic was found to be a helpful supplement for improving the productivity of laying hens. The addition of the probiotic Bacillus subtilis improved the egg’s feed efficiency, weight, and mass. Adding Bacillus subtilis to the eggs enhanced their albumen height and egg white quality (Haught unit) during the production cycle.

Effect of Probiotics on the Chicken’s Gut Health

Probiotics have several beneficial effects on the chicken’s gut:

  • they increase the absorption of nutrients, minerals, and vitamins B and K
  • they prevent bad germs from attaching to the gut
  • they change the actual shape of the gut’s inner surface
  • they strengthen the intestinal barrier

Nutrient absorption

Probiotics expand the accessible surface area for the absorption of nutrients. They affect villus height, crypt depth, and other intestinal morphological parameters. Crypts are the cells in the intestines that renew the intestinal lining and produce mucus.

Furthermore, probiotics seem to have a remarkable ability to regulate goblet cells. These goblet cells are epithelial cells inside the chicken’s intestine that serve nutrient absorption. Probiotics prevent dangerous microorganisms from adhering to the intestinal epithelium.


The degree of influence differs from strain to strain. A probiotic feed supplement with Lactobacillus casei, Bifidobacterium thermophilum, Lactobacillus acidophilus, and Enterococcus faecium boosts villus height while decreasing villus crypt depth. This boosts feed uptake and growth development.

Lactobacillus plantarum and Lactobacillus reuteri strengthen barrier integrity and reduce the admission of harmful bacteria. 


A probiotic cocktail of Bacillus licheniformis, Bacillus subtilis, and Lactobacillusplantarum can improve gut microbiota, histomorphology, and barrier integrity in heat-stressed broilers. It improves the quantity of Lactobacilli and Bifidobacterium and the height of the jejunal villus (in the central part of the small intestine).

Effect of Probiotics on the Chicken’s Immune System

Probiotics affect a chicken’s immune system in several ways:

  • they stimulate white blood cells (immune cells)
  • they boost natural killer (NK) cell activity
  • they boost antibodies IgG, IgM, and IgA
  • they stimulate viral immunity

White blood cells are the central cells of the immune system. They fight against infections and other diseases. NK cells are special white blood cells that can kill tumors and cells infected with a virus.

IgG, IgM, and IgA are immunoglobulins, antibodies that are produced by the chicken’s immune system in response to an infection. IgG provides long-lasting protection against infections. IgM provides rapid but short-lived protection as a quick response to new infections. IgA protects against pathogens in the chicken’s guts.

Viral Diseases

By stimulating the immune system at the cell level, probiotics can help alleviate viral infections like infectious bursal disease, Marek’s disease, and retroviral infections.

Using probiotics in chicks helps them protect against viral infections like Newcastle Disease and Infectious Bronchitis. Chicks that get probiotics while vaccinating for Newcastle disease show a better immune response and generate more antibodies. Probiotics also reduce the chances of secondary infections.


Feeding Lactobacillus sporogenes increased the immunity against Newcastle Disease in broilers fed 100 to 150mg/kg, 28 days after vaccination.


A study in 2015 examined the effect of Bacillus amyloliquefaciens on the immune responses of Arbor Acre broiler chickens. The findings suggest that Bacillus amyloliquefaciens reduces immune distress in immunomodulatory broilers at a young age. Intake boosted the lysozyme activity in plasma and raised the white blood cell count. Bacillus amyloliquefaciens might help to improve the growth performance and immunological condition of broilers exposed to immune stress at a young age.

How Probiotics Enrich Microbiota

A rich gut microbiota affects a chicken’s metabolism, growth rate, nutrition intake, and general well-being.

Probiotics can enrich the chicken’s microbiota by:

  • correcting microbial imbalances in the guts (dysbiosis)
  • lowering harmful species growth
  • boosting helpful bacteria
  • neutralizing and absorbing toxins (e.g. mycotoxins)
  • reducing Salmonella and E. Coli

One study supplemented a broiler’s diet with Bacillus coagulans when the birds suffered from a Salmonella infection. The diet increased the Bifidobacterium and Lactobacilli but decreased the Salmonella and Coliform concentrations in the chicken’s ceca.

Homemade Probiotics

Preparing and using homemade probiotics is not recommended. You never know the number and types of bacteria that are present in such homemade brews.

There are many cost-effective commercial products on the market that are safe to use for chickens.

That said, you can ferment apple cider. Fermented apple cider can be made at home with vinegar and offered to chicken as homemade probiotics. The fermented form of different grains can be used as homemade probiotics for chickens.

Risks of Probiotics for Chickens

Until now, there has been no real documented risk of probiotics for chicken.

Theoretically, excessive probiotic usage can lead to digestive issues, stomach allergy, and disturbed microbiota in the ceca. This could lead to reduced fiber digestion and deficiencies of vitamins produced in the ceca of chickens.

However, these issues have not been observed yet in chickens.

Frequently Asked Questions

Are probiotics safe for chickens?

Yes, unlike antibiotics, probiotics are completely safe for use in chickens. They are an all-natural supplement that boosts gut health and overall well-being.

Can probiotics prevent chicken diseases?

Yes, probiotics boost the chicken’s immune system and reduce infection-associated diseases like infectious bursal disease, chicken infectious anemia, Marek’s disease, Infectious Bronchitis, and Newcastle Disease. They also regulate Salmonella, E. Coli, and mycotoxins and prevent coccidiosis.

How do probiotics help with chicken digestion?

Probiotic bacteria take resources away from pathogens in the chicken’s gut. This process of competitive exclusion and bacterial antagonism boosts intestinal health. Probiotics also have the remarkable ability to morph and enhance the insides of the guts, enlarging the intestine’s surface to absorb more nutrients.

What are the side effects of probiotics in chickens?

Excessive probiotic usage in chickens can lead to digestive issues, stomach allergy, and disturbed microbiota in the ceca.

How often should I give probiotics to my chickens?

Supplements can always safely be added to a chicken’s diet at any age. However, probiotics are highly recommended for chicks after hatching, after a course of antibiotics, to control diarrhea, during peak production of laying hens, or during times of stress such as molting, moving, or heat stress.

Can probiotics replace antibiotics for chickens?

Since Europe banned antibiotics in chicken feed, probiotics are used more and more as an alternative to antibiotics. By boosting the immune system, they can prevent or reduce the need for antibiotics, but they can never replace antibiotics altogether, as antibiotics may still be necessary for severe infections.

How do probiotics impact egg production in chickens?

Chickens on probiotics lay more eggs of higher quality and better fertility. Probiotics enhance the hatchability of eggs and the quality of the albumen (egg white) and improve the cholesterol content of the eggs.

Where does the term ‘probiotic’ come from?

The term comes from the Greek phrase ‘pro bios’, which means ‘for life’, referring to the good bacteria in probiotics that are immediately colonized by the body when they are recognized as good germs.

What does DFM stand for in probiotics for chickens?

DFM stands for Direct-Fed Microorganisms. It refers to probiotics that are directly fed to chickens as a supplement in the feed or water. This is different from other methods, like probiotic-enriched feed or probiotic-infused litter.

Related Articles

  • Rooster Booster Poultry Cell: a broad spectrum vitamin, mineral, and amino acid supplement to boost chicken health when under stress
  • Rooster Booster Vitamins & Electrolytes with Lactobacillus: a vitamin and electrolyte supplement that also contains probiotics
  • Calcium for Chickens: Calcium is essential for chickens as it’s vital for egg production, controls heart rate and blood clotting, promotes a healthy nervous system, supports growth and development, boosts bone strength, activates digestive enzymes, and regulates the body’s pH.
  • Vitamin B12 for Chickens: Vitamin B12 is an essential vitamin for chickens that plays a core role in many vital body processes.
  • Vitamin K for Chickens: vitamin K is a group of 3 chemicals essential for blood clotting, biosynthesis of proteins, bone composition, and embryo development in chickens and poultry.
  • Vitamin D for Chickens: Vitamin D is essential for chickens, especially laying hens and chicks. It supports skeleton development and proper immune functioning.
Dr. A. Ibrar, DVM
University of Veterinary and Animal Sciences, IUB, Selçuk Üniversitesi

Dr. Ibrar A. is a licensed veterinarian with many years of experience on poultry farms and poultry feed. He has published several scientific articles on poultry diets, amino acids, and prebiotic usage in poultry. Dr. Ibrar is currently pursuing a Ph.D. in animal nutrition and nutritional diseases.

Chicken Fans Editorial Team

The editorial team consists of 3rd generation chicken owners Kat, journalist, editor-in-chief, and Nick, working with illustrators and specialists in the field.