The construction and operation of the gastro-intestinal tract of birds is completely different to mammals. It is extremely important for the health of your birds that the provided feed is tailored to the digestive system of your feathered friends. In a bird, the system is composed of the beak, the crop, the glandular stomach and the gizzard. These have their own specific task in the absorption and digestion of the provided food. We must ensure that each part can carry out its function as correctly as possible.
How a bird eats, depends on the type of bird. Certain types eat the seed an shell; others will use their beak and active tong to peel the seeds and leave the shell. Often, they will press the seed with their tongue against the hard palate to break it.
After they swallowed the feed, it ends up in the crop. This is a sack like widening of the oesophagus and is on the right-side of the neck just before the entry to the chest. The eaten food is stored and presoaked in the crop.
After the crop, there is the glandular stomach. This is an organ with a lot of glands which emit digestive juices and stomach acid on the pre-soaked seeds. The feed stays briefly in the glandular stomach, so that the juices can work on it. There often the feed is transported to the gizzard.
The gizzard is a round organ with a thick wall constructed of muscles. This is the last phase of the processing before it goes to the intestinal canal. The inside of the gizzard is covered with a very hard lining with a rough surface. The gizzard contracts strongly: together with the rough lining, this ensures that the food is ground down. If the food is already too far processed when it arrives in the gizzard, the continued grinding of the food will no longer have to carry out its function. This causes thinning of the wall and slackening of the gizzard which ultimately ends in Proventricular Dilatation Disease.
In order to support and strengthen the grinding action of the gizzard, the birds must always have bird grit and soluble grit. This is indispensable and is unfortunately often forgotten. The finely ground food then arrives in the small intestine where bile and pancreatic juices are added which further break down the food so that it can be absorbed.
In the large intestine, excess water is reabsorbed into the body. A difference should be made between birds that are seed-eaters and soft-food eaters. Seed-eaters have a longer gastro-intestinal tract as they have to digest a lot more carbohydrates. Birds that eat soft foods have a much shorter gastro-intestinal tract and digestion is much quicker. This of course influences the food which needs to be provided