174 POULTRY CULTURE 



Birds are most closely akin to reptiles, which differ strikingly from mam- 

 mals in the structure and use of the organs for the prehension of food and 

 also in the provision made for its final mastication. A cow may choke on an 

 apple; a snake by extension of the mouth and dilation of the gullet will 

 swallow animals which, even after constriction in its folds, have a circumfer- 

 ence greater than the normal circumference of its body. In this respect birds 

 occupy an intermediate position. A bird can usually swallow anything that it 

 can get into its mouth. In the young of aerial birds the mouth is conspic- 

 uously large. A small chicken will swallow an insect apparently much too large 

 for it ; fowls often kill mice and frequently swallow young mice alive ; l a goose 

 will swallow a large apple core. No one who closely observes the feeding 

 habits of poultry which have access to foods of various kinds, in pieces much 

 larger than they can conveniently swallow, can fail to notice that, even when 

 the bird has to pick the article to pieces to eat it, the last piece swallowed is 

 always much larger than is commonly considered an appropriate size for mor- 

 sels of its food. It has been usual to attribute this to gluttony and to the fear 

 of having a choice morsel snatched away, but it is simply the natural habit 

 of the bird to swallow the largest morsel adapted to its structure. 



The crop of the bird corresponds to the rumen, or paunch, in ruminant 

 quadrupeds, but in the provision for reducing food, after subjection to the 

 action of the secretions of the crop and proventriculus, a bird resembles the 

 orders below it in the scale of development. The food of the bird is masti- 

 cated, or triturated, in the gizzard. Reasoning from analogies observed between 

 birds and ruminants, and from the fact that small particles of stone, glass, 

 earthenware, etc. were often found in the gizzards of fowls in course of prep- 

 aration for the table, it was long ago assumed that the gizzard itself was inad- 

 equate for its function, and that the bird swallowed these substances because 

 they were required for the mastication of its food. One of the common pre- 

 cepts of poultry culture is that poultry must be constantly supplied with 

 " fresh, sharp grit " or it cannot properly digest its food, and the practice of 

 supplying the birds with the teeth that nature neglected to provide is quite 

 general. 



In respect to the gizzard, as in capacity for swallowing, birds are more like 

 some reptiles and insects than like the familiar animals with which their nutri- 

 tive organs are usually compared. The crocodile has an organ resembling a 

 gizzard, and some naturalists 2 have said that, like birds, crocodiles swallowed 

 stones to aid " the gastric mill." Some insects have gizzards supplied with 

 tooth-like processes. From these several analogies the reasonable presumption 

 is that the bird does not require grit to grind its natural food, and that, while 

 occasional eating of indigestible articles of this kind might be called an error in 

 selecting food, the regular consumption of such stuffs would indicate unnatural 

 feeding and an abnormal condition of the digestive tract as a result. This 

 point will be further considered in a subsequent paragraph. 



1 I have seen a very large Brahma hen swallow alive a mouse more than 

 half grown. 2 James Orton, Comparative Zoology. 



