The Chicken Digestive System and Immune System: An Important Partnership

By Jennifer Murtoff, Home to Roost LLC 

How are your chickens’ diet and their overall health connected?

Overview of Immune System

As humans, we rely on our immune systems every day to protect us from viruses, bacteria, toxins, and fungi. When this network of organs, cells, and proteins defeats a threat to our body, it makes a record of how to defend against the invader. The next time the body is faced with this particular attacker, the immune system can defeat it swiftly and efficiently.  

The chicken’s immune system functions in a similar way. It is also complex. Its main defenses are lymphoid organs, which produce, store, and carry cells that fight infection. The primary lymphoid organs in a chicken are the thymus and the bursa of Fabricius:

  • Thymus: This series of lymphatic lobes runs almost the whole length of the neck. It is similar to the thymus in humans.
  • Bursa of Fabricius: This organ is unique to birds and is located on top of the rectum. It forms a kind of pocket (the word bursa means “purse”) that contains folds of lymphoid tissue.

These two organs produce immune cells: the thymus produces T-cells and the bursa of Fabricius produces B-cells. These immune cells migrate to other areas in the body, including the Harderian gland, spleen, and bone marrow. However, more than 60% of these immune cells migrate to and reside in the various places in the digestive tract, including the cecal tonsils and Peyer’s patches. From these locations, they defend the body against invaders.  

In addition to hosting immune cells, the digestive system also contains other important components that support the chicken’s immune system. Beneficial microflora (bacteria and yeast) live in throughout the digestive tract. They provide important services, such as protecting the walls of the intestine from colonization by harmful bacteria. Scientists also think that the friendly microflora help keep the bird’s body on high alert for disease-causing organisms.

So, the immune system of a chicken includes both immune cells and beneficial microflora that are located in the digestive tract.

Benefits of a Diet That Supports the Immune System

You can help keep your chickens healthy by providing a high-quality, commercially formulated feed containing elements that are necessary for gut health. These include probiotics, prebiotics, yeast culture, and essential oils. These ingredients populate the gut with good microflora and can boost the immune system. Studies have shown that feeds formulated to boost the immune and digestive systems can result in better health and quality of life and improved egg production and quality. In addition, healthy chickens are less likely to harbor harmful bacteria in their reproductive tract, meaning safer eggs for you.

Finally, a diet that supports the immune system can increase absorption of nutrients from food by increasing the surface area of the intestine, meaning your birds will use their feed more efficiently. It also aids in digestion of calcium, which is important for strong eggshells and healthy bones.

In short, a chicken with a diet that supports a healthy immune system is a chicken that is both happy and productive, living her best life.

Support Your Chickens’ Immune Systems

Nutrena® NatureWise® Poultry feeds with FlockShield® and essential oils are specially formulated to support both the digestive system and the immune system for birds at every stage of life. They contain probiotics, prebiotics, yeast cultures, and essential oils that contribute to gut and immune system health. Choosing Nutrena NatureWise with Flockshield will help your birds live their best lives by improving their health, digestion, and productivity.

Choosing the Right Chick Feed

By Jennifer Murtoff, Home to Roost LLC

Did you know that choosing the right chick feed can help your chicks develop healthy digestive systems? A healthy digestive system is key to a healthy chicken. It aids in the development of the immune system and promotes absorption of nutrients. Professionally formulated feeds provide your birds with proper nutrition at all stages of life.

The Importance of Chick Feed

Chicks need a feed that is different from adult layer feed. Chick starter-grower feed is 18% protein, compared to 16% to 18% in a layer ration. Chicks grow very quickly, and they need more protein to support their bodies in this important process.

Chicks also need less of certain vitamins and minerals that are necessary for laying hens. For example, chicks do not require as much calcium as laying hens; in fact, too much calcium can cause kidney damage. Be sure your chicks get a starter-grower feed, rather than a layer ration. At 16 weeks, you can switch from starter-grower to a layer diet.

Gut Microflora

A nutritionally balanced diet with proper amounts of protein, vitamins, and minerals supports your chicks’ growth. Some diets also provide gut bacteria for an extra healthy start! When chicks hatch, they have no gut bacteria. They develop their gut bacteria by consuming some of their mother’s droppings and absorbing her microflora [MY-kruh-FLOOR-uh], gut-friendly organisms that include certain kinds of bacteria and yeast. These tiny living things populate the digestive system, aid in digestion, and prevent harmful organisms from flourishing in the gut.

However, many chicks are hatched and brooded by humans, rather than a hen, and will not get supplemental microflora until they are allowed access to the outdoors. In fact, chicks that are raised in a completely germ-free environment develop inferior digestive systems. If your chicks are not raised by a mother hen, they will benefit from a high-quality feed that contains the varied elements necessary for gut health.

Some feeds provide the following components for an extra-healthy boost:

  1. Fungal Components: Also called yeast cultures or fermentation metabolites, these additives are made up of beneficial compounds produced by fermentation of dietary yeast. When added to a chicken’s gut, yeast culture supports the immune system and gut microflora.
  2. Probiotics: These live microorganisms aid in digestion, support the existence of beneficial bacteria, and can protect against bad bacteria. They also help the gut to better absorb nutrients and can prevent or cure diarrhea. Here are a few you will see on feed labels:

ProbioticPronunciationPurpose
Lactobacillus acidophilus[LAK-toh-buh-SI-luhs a-suh-DAH-fuh-luhs]Helps ferment carbohydrates in feed, produces compounds that support growth, reduces impact of harmful micro-organisms
Lactobacillus casei[LAK-toh-buh-SI-luhs KAY-see-eye]Helps ferment carbohydrates in feed, reduces colonization of bad bacteria, reduces impact of harmful micro-organisms
Bifidobacterium thermophilum[bye-fih-DOH-bak-TEER-ee-um ther-muh-FIH-lum]Helps ferment carbohydrates in feed, benefits immune system
Enterococcus faecium[en-tuh-row-KAW-kuhs FEE-see-um]Helps ferment carbohydrates in feed, reduces impact of harmful micro-organisms

  1. Prebiotics: The prefix pre- means “before,” and prebiotics pave the way for probiotics to do their job. They serve as food for good bacteria, supporting their growth and strengthening the chicken’s ability to resist bad bacteria.

  1. Essential Oils: Some poultry farmers are integrating essential oils into their birds’ diets to promote flock health and prevent disease. These plant products are distilled from leaves, flowers, stems, and roots. Some backyard chicken owners regularly use herbs because they believe they have antimicrobial, astringent, and antifungal properties, as well as the ability to repel insects. Essential oils from these plants are also making their way into chicken feeds.    

Some essential oils act as antioxidants in poultry, protecting the intestine and boosting the immune system. This antioxidant function can be beneficial for chicks early in life, when their immune systems are developing. Proprietary research has shown that chicks fed a diet that includes essential oils grow more quickly, developing good lean muscle mass with less body fat, and have better vitality. They also consume less feed, indicating that their bodies are processing the feed more efficiently. 

Learn more about NatureWise® Chick Starter Grower with FlockShield™ and essential oils, which promotes gut health and supports your birds’ immune systems, leading to a healthier flock. Using a combination of oregano, thyme, rosemary, star anise, these new poultry diets support the vitality of your chicks.  

Feeding Tips

Here are a few tips to help your chicks on their way to living their best lives.

  • Learning what to eat: After your chicks have learned to drink, scatter some feed on the floor of the brooder. They will naturally start to peck at it. You can tap your finger on the feed, similar to how a mother hen uses her beak to show the chicks where the food is.
  • All-day buffet: When you hatch or bring home your chicks, you’ll want to provide chick starter-grower feed 24/7.
  • Using a proper dish: Provide starter-grower feed in a chick feeder, which is a shallow dish with a lid. The lid has circular holes cut in the top to allow the chicks access to the feed. This prevents the chicks from dusting or sitting in the feed. It also helps keep droppings and bedding out of the feed.
  • Feeding (and limiting) treats: After 6 weeks, you can provide treats such as scratch grains, mealworms, or kitchen scraps. If they eat anything other than starter-grower, provide fine grit in a separate feeder. This will help them digest these foods. Be sure to give treats for only 15 minutes once per day and remove what they don’t eat. About 85% of their diet should come from a formulated feed, rather than from treats.
  • Duration for feeding starter-grower: Continue to provide chick starter-grower until the chicks are about 16 weeks old. Then it’s time to switch to layer ration. (Note: Meat birds have different dietary requirements.)
  • Providing clean feed and water: Make sure to keep your feeders clean, even if that means dumping out soiled food. Also be sure your chicks have access to fresh, clean water at all times.

Medicated Feed, Nonmedicated Feed, and Coccidiosis Vaccines

You’ve no doubt heard of medicated feed, and you may be wondering about what it does and if it would benefit your chicks. Here are some facts to help you decide whether to use medicated feed.

Medicated feed helps chicks develop resistance to one organism: coccidia. These parasites live in the soil and their oocysts, similar to eggs, invade a chick’s digestive tract. The parasites cause a disease called coccidiosis. Most cases occur at 4 to 5 weeks of age and can produce bloody droppings. The chicks stop eating and growing and may be hunched with fluffed-up feathers.

Most retail medicated chick starter and starter/grower feeds use the drug amprolium to control coccidia and allow chicks’ immunity to coccidia to develop. Retail medicated feeds have low levels of amprolium that are toxic for coccidia but safe for other species. Amprolium reduces the amount of thiamine available in the intestinal tract of a chick, and coccidia will die without enough thiamine from their host. The amount of thiamine allows some coccidia to remain alive in the chicks’ digestive system. The birds’ bodies then can build resistance to the parasites without dying from the infestation.

A second line of attack against coccidiosis is a live vaccine. The vaccine works differently from medicated feed. The vaccine contains a controlled amount of live coccidia, which allows chicks’ immune systems to develop resistance. You can ask your hatchery to vaccinate for coccidiosis when you order your chicks. If you purchase chicks from a store or farm, always ask if they have been vaccinated for coccidiosis. Note that the vaccine is not 100% effective. It does not prevent against all strains of coccidia.

  • For chicks that ARE vaccinated for coccidiosis, there is no need to provide medicated feed.
  • For chicks that ARE NOT vaccinated for coccidiosis, DO provide medicated feed.

Regardless of whether you choose the vaccine or the medicated feed, make sure to provide a warm, clean, draft-free brooder to further protect against coccidiosis.

Facts about Medicated Feed with Amprolium

  • Amprolium is the most popular drug used in medicated feed.
  • Medicated feed protects ONLY against coccidiosis. It does not protect against Marek’s disease or parasitic worms, such as roundworms (ascarids). It is not an antibiotic. 
  • Medicated feed is not a cure for coccidiosis. If your chicks get sick, medicated feed will not help them.  
  • Too much amprolium can cause serious vitamin deficiencies. Follow all written product instructions for medicated feed and other products containing amprolium.
  • If you use a medicated feed, do not provide liquid-solution amprolium (Corid) in drinking water.
  • If amprolium is fed to waterfowl, it is off-label use and should be done under advice from a veterinarian.

See the post “Medicated Chick Starter Facts” for more information on medicated feed.

The next time you examine a feed label, keep these points in mind. Now that you know more about chick feed ingredients, you can get your birds off to a healthier start and well on their way to living their best lives.

Chicken Feeds: They’re not all the same.

Did you know that a quality chicken feed is more than just grains, vitamins, and minerals? While these ingredients are necessary, they are only part of a diet that helps your birds live their best life. Quality, higher-technology feeds include beneficial microflora, which are gut-friendly organisms such as bacteria and yeast. These tiny living things populate the chicks’ digestive systems, aid in digestion, and strengthen the chicken’s immune system.

Let’s at look some of these added extras that contribute to a chicken’s digestive health. Then you’ll know what to look for when you’re looking for your next feed.   

Fungal Components

The next time you look at a feed label, check for the words yeast culture. Also called fermentation metabolites, this additive is composed of compounds produced by fermentation of dietary yeast, including Saccharomyces cerevisiae (sak-uh-roh-MY-seez sehr-uh-VEE-see-eye). When fermented inside a chicken’s gut, yeast culture has the following functions:

  • Supports the immune system and gut microflora
  • Contributes to the health and strength of intestinal tissues
  • Produces compounds that latch on to bad bacteria such as E. coli and Salmonella and prevent them from attaching to the cells of the digestive tract

Another fungal product involves the fermentation of Trichoderma reesei (trih-kuh-DER-muh REE-see-eye). This feed component is an enzyme source, and the compounds it produces help break down carbohydrates to make nutrients more available to the chicken.

Probiotics

You’ve seen probiotics intended for humans, but did you know that probiotics are also helpful for your chickens? Probiotics are live microorganisms that result from fermentation and aid in digestion. Around 70 percent of the bacteria in a chicken’s digestive tract is Lactobacillus strains. They support the existence of beneficial bacteria, and some protect against bad bacteria. Many of these microorganisms are found in several places in the digestive tract. Look for these probiotics on feed labels:

  • Lactobacillus acidophilus (LAK-toh-buh-SI-luhs a-suh-DAH-fuh-luhs): Helps ferment carbohydrates, produces chemicals that support growth, reduces impact of harmful microorganisms
  • Lactobacillus casei (LAK-toh-buh-SI-luhs KAY-see-eye): Helps ferment carbohydrates, reduces colonization of bad bacteria, reduces impact of harmful microorganisms
  • Bifidobacterium thermophilum (bye-fih-DOH-bak-TEER-ee-um ther-muh-FIH-lum): Helps ferment carbohydrates, benefits immune system
  • Enterococcus faecium (en-tuh-row-KAW-kuhs FEE-see-um): Helps ferment carbohydrates, reduces impact of harmful microorganisms

When probiotics form part of the chicken’s microflora, they support the immune system and reduce disease. They also help the gut better absorb nutrients and can prevent or cure diarrhea.

Prebiotics

The prefix pre means “before,” and prebiotics pave the way for probiotics to do their job. They serve as food for good bacteria, supporting growth and strengthening the chicken’s ability to resist bad bacteria. When they are fermented by a chicken’s body, they create compounds that stop the growth of harmful bacteria and keep them from sticking to the intestinal walls.

Prebiotics cannot be broken down and absorbed by the digestive system. After the chicken eats prebiotic material, some remains in the crop. However, most prebiotics travel into the lower parts of the digestive tract, including the ceca. Here they aid in fermentation and balance the acidity of the ceca for optimal health.

Some of these prebiotics might appear on the feed label, or you can supplement your chickens’ diet with these common sources of prebiotics:

  • Flaxseed
  • Barley
  • Berries
  • Dandelion greens
  • Kelp
  • Garlic
  • Honey
  • Wheat bran
  • Yams
  • Lentils

While technically not a prebiotic, yeast culture has properties that can be included in the prebiotic category. It assists with nutrient absorption and digestion and produces compounds that can improve growth and enhance the immune system.

What to Look for on the Label

The next time you buy feed, read the label closely. There are two main sections to every feed label:

  • Guaranteed analysis lists the percentages of ingredients that the feed is certified to contain.
  • Ingredients includes everything that is found in the feed.

Look for probiotics, such as Lactobacillus strains, in the Guaranteed Analysis and Ingredients. The fungal products will appear in the Ingredients section only.

The next time you choose a commercially formulated feed for your flock, remember to look for yeast culture, prebiotics, and probiotics. These important ingredients will give your chickens some extra love and help them live their best lives.

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