378 FEEDS AND FEEDING, ABRIDGED 



In aggregate value the annual yield of poultry and eggs in the United 

 States amounts to $750,000,000, exceeding the value of all the gold, 

 silver, iron, and coal mined annually in this country. According to 

 the Census of 1910, over 88 per ct. of all the farms reported flocks of 

 poultry, the average farm income from poultry for these farms being 

 $105, in addition to the eggs and meat consumed on the farm. The 

 value of the eggs produced in this country amounts to about twice as 

 much as the value of the meat. 



Of the total number of poultry in the United States, about 95 per ct. ' 

 are chickens, about 4 per ct. ducks, turkeys, and geese, and the remain- 

 ing 1 per ct. guineas, pigeons, pheasants, and other domestic birds. 

 Because of their importance, the following discussions deal al- 

 most entirely with chickens. The popularity of chickens is due to the 

 fact that they are usually much better egg producers than the other 

 species and that they, moreover, furnish a most convenient source of 

 fresh meat on the farm. 



The digestive system of poultry.— The digestive tract of poultry is 

 quite different from those of the larger farm animals. Poultry have 

 no teeth with which to chew their food, the teeth and lips being replaced 

 by a horny mandible on each jaw, which forms the beak, or bill. Such 

 soft feeds as vegetables, green herbage, or meat can be torn into pieces 

 by the beak, but hard substances like grain are swallowed whole. Since 

 no chewing is done in the mouth, abundant saliva is not needed and 

 the salivary glands are imperfectly developed. 



From the mouth the food is forced down the gullet into the crop, a 

 pouch-like enlargement of the gullet just before it enters the body 

 cavity. No enzymes are secreted in the crop, but the feed is softened 

 as in the paunch of ruminants, such hard materials as grain remaining 

 in the crop about 12 hours. From the crop the food passes thru the 

 second part of the gullet into the glandular stomach, where the gastric 

 juice is secreted. Passing thru the glandular stomach, the food, with 

 the acid gastric juice, enters the gizzard, or muscular stomach. This 

 is a powerful, muscular grinding apparatus, with a tough, horny lining, 

 and in it the food is finely ground with the aid of small stones and 

 grit. The gizzard has a truly remarkable grinding and crushing 

 power, being able to bend pieces of iron and wear smooth the edges of 

 pieces of broken glass. 



From the gizzard the partially digested food passes into the small 

 intestine, in which the digestive processes are similar to those in the 

 other farm animals. The large intestine in poultry has but small ca- 

 pacity. It consists of a small rectum and two caeca, or blind guts, at 

 the juncture of the small intestine and the rectum. A further pecu- 

 liarity of poultry is that the urine and feces are not voided separately, 



