The Avian Digestive System Poultry are opportunistic feeders and must, as a matter of efficiency, select foods that are not only high in energy but also high in protein, minerals and vitamins. Digestion in the Chicken involves a series of processes in the alimentary tract by which feeds are broken down in particle size and finally rendered soluble so that absorption is possible. Solubilizing the food is critical to digestion and is accomplished by a combination of mechanical and enzymatic processes. They synthesize or break down chemical compounds, or transform them from one type to another.
Enzymes are very specific in the reactions they catalyze.
The Mouth consists of the upper maxilla and the lower mandible and is called the beak. Salivary glands located here, secrete a very limited amount of amylase, which hydrolyses starch to maltose, and maltase which hydrolyses maltose to glucose. The salivary glands main purpose is to lubricate the bolus, which is the portion of food swallowed at one time, so that it can move down the digestive tract. Very little digestion takes place in the mouth because food passage is so fast. Chickens lack a soft palate in their mouths and the hard palate is divided by a long, narrow slit in the center, opening into the nasal passage.