Does my chicken's crop look normal? Is my chicken having diarrhea? Why is my chicken eating rocks? If you're asking yourself any of these questions, you might wish to learn a bit more about how your chickens eat, digest, and excrete their food. Chickens have some organs that are similar to mammals such as large and small intestines, pancreas, and liver, but other aspects of chicken anatomy are very different and can be confusing to new chicken owners. Here's an overview of how a healthy chicken's digestive system works.
Pecking and Swallowing
Chickens are omnivores and will probably eat just about anything you feed them. However, that doesn't mean that they should eat anything. Healthy chickens eat foods such as corn, seeds, greens, worms, and more. Chickens also eat grit, or small stones, to help them chew their food, since they don't have teeth. In order for your chickens to be healthy, it's very important that you research what your breed of chicken should be consuming.
As human children, we were always told to not swallow without chewing our food. Chickens, however, don't have any teeth! Instead, they simply gulp down their food whole. In the chicken's mouth, food is mixed with a small amount of saliva and digestive enzymes. Next, the food travels down the chicken's esophagus and is temporarily stored in their crop to be digested later. A chicken's crop will naturally look larger after eating since they have food stashed there. Food can stay in a chicken's crop for up to 12 hours, and it is slowly sent down the esophagus to the next destination.
After exiting the crop, the food moves down into the chicken's version of a stomach, called a proventriculus. Similarly to the stomach of mammals, the food is mixed with hydrochloric acid and other enzymes to help digest it. However, the food still hasn't been chewed yet. This happens in the second sort of "stomach" called the gizzard. In the gizzard, the food is ground up by small stones (or grit) that the chicken ate earlier. Make sure that you keep small pieces of metal and glass away from your chickens, because sharp objects will get stuck in the chickens' gizzard and poke a hole in it, eventually killing your chicken.
Next, the food is digested further in the small intestines, pancreas, liver, and gall bladder. The large intestines then remove nutrients from the food. After the large intestines, the chickens have ceca, which are two pouches where they extract more nutrients by fermenting the remainder of the food that isn't digested yet. Every day, the chicken empties its ceca with an excrement that is pasty and light brown. The final parts of the chicken's digestive system are the cloaca and the vent. In the cloaca, urinary waste is mixed with the digestive waste, since chickens don't have bladders. Finally, the waste is excreted through the vent.
Common Digestive Problems
Some common chicken digestive problems include an impacted crop, sour crop, or pendulous crop. An impacted crop means the opening to the esophagus from the crop is blocked. This happens because something has gotten stuck in the crop such as string or tough, long pieces of grass. Your chicken might have an impacted crop if its crop is always full even if it hasn't eaten in a while, if the crop feels hard, or if the chicken is acting out of the ordinary. Sour crop is a yeast infection in the crop, similar to thrush in humans. A sign of sour crop is that the crop is full and feels squishy, the bird's breath smells sour, or the bird has white patches in the mouth. Pendulous crop is when the crop has been stretched out and swings lower than it normally would. Pendulous crop can sometimes be caused by an impacted crop. The chicken may seem like it's okay, but the muscles in the crop are being damaged and require medical attention.
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