The Digestive System of a Chicken

The digestive system of a chicken breaks down food mechanically and chemically. Nutrients are absorbed for use in the body. A knowledge of the basic path that food takes and the digestive process of chickens helps our understanding of nutritional requirements as well as other factors such as health problems our birds can encounter such as worms.

Starting at the beak, food is moistened with saliva. This contains a starch-reducing enzyme. Food is swallowed without chewing and passes down through the oesophagus (which is flexible) down to the crop. The crop is a pouch at the base of the neck that stores food. The oesophagus then carries food to the proventriculus where it is mixed with acids and digestive enzymes. Grit accumulates in the gizzard, which with a strong muscular action, grinds the food down. The first part of the intestinal tract is called the small intestine. Food is reduced further with enzymes excreted by the pancreas. These enzymes break down protein. Bile that helps with fat digestion is produced by the liver (stored in the gall bladder) is added here. Digestion is taking place in the intestines which gives our chicken energy for all of that scratching around!

The caeca are a pair of tubes that allow fermentation of undigested food to take place. This looks like a dark mustard colour froth that is expelled once a day. The last part of the intestine is very short and is called the large intestine. This is where a chicken absorbs most of its water as well as a few remaining nutrients. The cloaca, also commonly called the vent is where faeces, urine and eggs pass through..... little explanation required of what happens here!