CHAPTER V 

 Diseases of the Alimentary Tract 



The arrangement of the digestive organs in birds differs 

 from that in other domestic animals in that the mastication 

 of the food does not take place in the mouth. The food of 

 birds, consisting mainly of grains and seeds, is swallowed 

 whole into the crop. It remains here until it is completely 

 softened by the juices secreted by this organ. The food then 

 passes into the stomach (proventriculus), where it is mixed 

 with still other juices, and then into the gizzard. The 

 muscular walls of the gizzard grind the softened food against 

 the small pebbles (grit) which the bird picks up, until it 

 becomes a paste. This paste is then passed into the intes- 

 tines and mixed with the secretions from the liver, pancreas 

 and the intestines themselves. The nutritive elements of 

 the food are transferred through the intestinal walls, by 

 means of the activity of the cells composing these walls, 

 into the blood and are carried to various parts of the animal 

 to be used in building up the tissues. 



In the wild state birds are forced to hunt for their own food. 

 They go about gathering in a few seeds here and there but 

 probably at no time is the crop overloaded. Under condi- 

 tions of domestication birds are fed only once or twice a 

 day and thus the crop is often gorged with a day's supply 

 of food. Further the lack of suflScient grit, lack of exercise 

 and the feeding of rich, soft mashes cause the birds to be 



67 



