We all want to make sure our chickens are happy and healthy. Just like us humans, diet and nutrition are essential for the overall health of chickens. The following article focuses on the gastrointestinal (GI) tract of chickens and how best to keep our birds happy and healthy with respect to diet and nutrition.


Gastrointestinal Tract of a Chicken

From start to end, a chicken’s digestive tract is quite different than our own, though there are some analogous parts between our two species. The chicken picks up food with its beak and secretes saliva to help moisten the food. However, unlike humans, chickens don’t have teeth, so all the food they pick up is swallowed whole. The esophagus is the tube that carries the swallowed food down to the crop of the bird, which is a storage area for food and water. Normally, the crop will only hold food for up to two hours. The crop also helps by starting the process of breaking down the food before the food is passed to the proventriculus to be more fully digested. After the proventriculus, the mostly-digested feed is passed along to the ventriculus (also known as the “gizzard”), which mechanically grinds the feed into smaller pieces. Since chickens don’t have teeth, the ventriculus “chews” their food instead! From the ventriculus, the ingesta passes to the intestines, where digestion is completed, and nutrient absorption occurs. All liquid and solid waste then leaves the chicken through the cloaca.



With so many different feeds available for chickens, how are you to pick the best one for your chickens and their gastrointestinal health? As with most decisions, there are trade-offs between each type of feed, but the most important factor is to choose a well-balanced diet with appropriate nutrients for the age and purpose of your birds. A growing pullet will need different nutrients than a laying hen, who will need different nutrients than a broiler!


Commercial Feeds

Commercial feeds are often cheaper than making your own feed and are already formulated and balanced for the types of birds that they are marketed for. They are also available in a variety of textures: mash, crumble, and pellet. Mash feeds are the most easily digestible, but pelleted feeds tend to be less wasteful as it is harder for chickens to kick it around! If you are set on making your own feed, just remember it is extremely difficult to balance the diet appropriately, so make sure to consult the Nutritional Requirements for Poultry by the National Research Council and/or your poultry veterinarian. You want to ensure you aren’t depriving your birds of essential nutrients or overloading them with too much of one nutrient!


Treats & Scraps

Treats and scraps can be given as a special snack for your hens, but make sure these only make up a small portion of their day’s feed. After you’ve worked so hard to find a complete, balanced diet for your hens, the last thing you want to do is cause nutritional disorders from displacing too much of their balanced diet with treats! Small changes in diet can affect the quality of the eggs they produce and their overall health!



As you have probably guessed, there are several nutritional disorders that can cause digestive problems in birds, but a common problem caused by improper diet is fatty liver hemorrhagic syndrome. This is caused when chickens have too high of an energy intake and fatty accumulates in their liver. The fatty liver lobes can rupture, causing death. Fatty liver hemorrhagic syndrome is often seen in older, obese birds and is typically caused by over-consumption of “junk food” like scraps, chicken scratch, and other treats. Prevention of this syndrome comes with providing a balanced diet to your birds and keeping them a healthy weight!



Coccidiosis or “avian intestinal coccidiosis” is the overgrowth of any species of the protozoal gastrointestinal parasite, coccidia. These single-celled organisms can thrive in your chickens’ guts, causing diarrhea, anemia, suboptimal growth, and even death. Though coccidiosis typically affects younger chickens due to the natural development of resistance against coccidia with age, it is possible for adults to be affected as well. This can occur if your birds have an unhealthy gut. Birds become infected if they ingest coccidia eggs from their environment. These eggs are shed in the feces of various animals and can remain viable for months in the environment, including in soil, litter, and feed.


Luckily, prevention of coccidiosis is fairly easy, as chicks and pullets can simply be fed a medicated feed with added coccidiostats to reduce the number of harmful protozoa in their gastrointestinal tracts while they develop their natural resistance. Management of litter moisture is also important in preventing coccidiosis—you don’t want your litter too dry or too damp! Also, if you have a mixed age flock, keep in mind that older birds who aren’t showing symptoms can still be shedding coccidia eggs in their feces, infecting the younger chicks.


Coccidia can be diagnosed by your veterinarian. Though fecal samples are a quick way to diagnose coccidia, false negatives are relatively common due to the intermittent shedding of eggs in feces. Therefore, some veterinarians may suggest performing necropsies or multiple fecal samples to definitively diagnose coccidia. Once diagnosed, your veterinarian can prescribe medication to treat your flock.



Roundworms, or ascarids, are one of the most common types of worms that can be found in chickens. They are long, yellow-white worms that live in the intestines and can cause droopiness, weight loss, and diarrhea in heavily parasitized birds. Death may occur due to intestinal obstruction if birds are immunosuppressed or have another disease that exacerbates obstruction, but typically roundworms do not cause high mortality in birds. Birds can get roundworms from the feces of other birds, including wild birds, or insects. You can help minimize the risk of your birds becoming infected by keeping your coop and the surrounding area clean and practicing good biosecurity.


So should you de-worm your chickens prophylactically then? Even though the idea of having worms living in your chickens may sound horrifying, having a low burden of worms may actually help develop their immune system, so it isn’t necessarily recommended to de-worm prophylactically. However, if you start seeing worms in stool or coming out of your chickens’ vents, it may be time to intervene with a de-worming medication. The only medication approved for treatment of internal parasites in egg-producing and meat birds is Piperazine. However, because worms can develop resistance to Piperazine, this is another reason to use de-wormers judiciously and only when clinical signs are seen, or if a veterinary professional deems it necessary.


Gastrointestinal Impactions

Another digestive issue that is seen in backyard poultry is gastrointestinal impactions. These are caused by ingested material causing blockages in the gastrointestinal tract. The most common culprit of impactions is forage material, though ingested substances that swell up in the gastrointestinal tract can also cause problems. These include feed, such as dry grains and bread, and other miscellaneous material such as litter.


So how do you keep gastrointestinal impactions in your birds? You certainly shouldn’t remove all their bedding, feed, and forage, but certainly you should take care in the management of these things and the general management of your flock to help prevent impactions. Often times the consumption of non-nutritive substances is an abnormal behavior due to stress or nutrient deficiencies. If you find your birds eating non-nutritive substances, take some time to determine any potential stressors or discuss their diet with your veterinarian. Do your hens seem to start eating litter when your dog is out in the backyard? Are they getting too many scraps? Questions like these are good to consider!


In contrast to the consumption of non-nutritive substances, your flock obviously has to eat, and that includes feed and possibly some forage. Avoiding food that can expand in their stomach or soaking these treats in water before feeding them to your hens is a good way to mitigate impactions due to feed. Forage material can be caught and knotted up in the digestive tract, especially if it is found in long strands, so it is especially important to manage the forage your chickens have access to: either make sure forage is cut short or limit your flock’s access to long forage! In addition, supplying your chickens with grit that is small and rough can help them grind up problematic ingesta in their gizzard.


In terms of treatment, some people have success simply providing a laxative to their hens for the impaction to pass naturally, but more severe impactions may require surgical intervention. As with most things, prevention is significantly easier than treatment!


While the issues listed above are among the most common digestive ailments of backyard chickens, this article is not a comprehensive list of digestive issues in chickens. Other diseases, such as Marek’s Disease, can also exacerbate these digestive issues in your hens. If you are concerned about digestive issues in your chickens, talk to your local veterinarian in order to properly diagnose and treat any potential afflictions.


This article was written by Anny Huang and Dr. Maurice Pitesky at the UC Davis School of Veterinary Medicine-Cooperative Extension. Anny Huang was recently accepted to the UC Davis School of Veterinary Medicine class of 2023!