190 



COMMERCIAL POULTRY RAISING 



form that the blood can absorb them, they are distributed 

 throughout the body as required. Water is a great aid in this 

 respect, in that it softens the food in the crop and prepares it for 

 the grinding process in the gizzard. It also serves as a carrier 

 in transporting the food through the digestive tract, and being a 

 liquid it dilutes the digested elements so that they can be more 

 readily absorbed. 



(Courtesy Cornell Experiment Station) 



Fig. 128. — Simple type of outdoor feed hopper. Cover is made water-tight 

 by means of patent roofing material. 



Nutrients. — Those portions of the food which >'ield heat or 

 energy or serve the body in any way are termed nutrients. 

 Nourishing elements would be another way of expressing the 

 parts or constituents of food. They are classified in five groups, 

 as follows: (i) water, (2) protein, (3) carbohydrates, (4) fats, 

 (5) ash. 



