The intestinal canal of the birds, like that of the mammals, is divided into the small intestine, intestinum tenue, the large intestine and the intestinum crassum. In the small intestine three sections can be distinguished according to morphological features: duodenum, jejunum, ileum.
The large intestine consists of the two caudal bowels, the short rectum and the cloaca The length of the intestine depends on age, breed, and the type and amount of food. Its approximate length, measured from the pylorus to the cloaca, is 5 to 6 in the hen body length Characteristic of the poultry is the diameter of the intestine, it is about the same size from the pylorus to the cloaca and decreases only imperceptibly
The small intestine serves primarily for digestion. It is divided into duodenum, jejunum and Ileum. The terminal or large intestine, intestinal crassum, of birds is scarcely greater in its lumen, even thinner in the lumen than the small intestine. It consists of the two caudal bowels and the short rectum caeca are paired, their base is mostly a little bit narrower thick-walled, with an incomplete sphincter. In the base part of the cecum come the mucous membranes and in the apexwärtigen lymphoepithelial storage, Lymphonoduli aggregati, which are known as Tonsilla caealis