No. 4.] FEEDS AND FEEDING. 13 



first. The part of the intestines extending from the ceca 

 to the anus is called the rectum. The enlargement of the 

 intestine just forward of the vent is called the cloaca. It is 

 a reservoir where the f^ces gather before being expelled from 

 the body. The urinal duct opening into this reservoir is a 

 very important factor in studying the digestibility of feeds 

 in poultry. The fact that the urine and the faeces mix before 

 being expelled makes it very difficult to study the digestion 

 of protein, particularly because in the faeces we find the un- 

 digested portions of the feed and in the urine the nitrogenous 

 materials that come from the broken-down cells of the body. 

 As these mix before being expelled, it is very hard to deter- 

 mine how much of the nitrogen comes from the indigestible 

 portions of the feed and how much from the urine. The en- 

 tire length of the digestive apparatus. of the hen is about five 

 feet, varying somewhat in different individuals. Some think 

 that there is a relation between its length and egg production, 

 but more data will be needed to verify this theory. 



The process of digestion is somewhat as follows : the food 

 is swallowed by the hen and remains in the crop for a time 

 to be softened. It then passes into the stomach, where it is 

 mixed with gastric juice which acts upon certain portions of 

 the food. From here it passes into the gizzard, where it is 

 ground and thoroughly mixed with the gastric juice already 

 mentioned. It then leaves the gizzard by way of the intes- 

 tines, where it is mixed with bile from the liver and pan- 

 creatic juice from the pancreas. These are very powerful 

 digestive juices, and most of the food is accordingly digested 

 in the duodenum, or the first twelve to eighteen inches of 

 the intestines ; but there is also an intestinal juice secreted 

 by the lining of the intestines that acts upon the undigested 

 portions of the food and completes digestion. The digestive 

 apparatus of the goose or the duck differs from that of the 

 hen in that there is no crop. The feed they eat remains in 

 the gullet, which becomes more or less distended, until it 

 passes through the stomach to the gizzard. This difference 

 is probably due to the early habits of the birds. The geese 

 and ducks, being water fowl, were able to eat food almost 

 continually, whereas the original hen found it necessary to 



