FEEDWa FOR EOG PRODUCTION 



199 



as containing round follicles, each one of which is the first 

 stage in the development of the egg, and are called the ova, 

 or yolks. The ovum, or yolk, develops in about two weeks, 

 during which time it is enclosed in a sack composed of mem- 

 brane. While so enclosed the yolk receives by means of the 

 blood the material that composes it. At the end of two 

 weeks, when the yolk reaches its full development, the 

 membraneous sack is broken and the yolk enters the funnel- 

 shaped opening of the oviduct, which will be noted in the 

 center of Figure 199. As soon as the yolk enters, the white 

 of the egg, or albumen, is secreted as the yolk proceeds 

 through the oviduct. After a sufficient amount of the albu- 



*■ {mwerol 7naTrer\ 



-^'Sone. 



'rProtein' 



Stare/, ^Wiy-Ctl'nFreeEi^l-r-act, 

 sugarn] ' 



D7r£J:^rp roh/zj 



z:ee 



Figure 198. — Chart showing how the elements of the feed go to meet the body 

 requirements and to produce the finished product. 



men, or white, is secreted to surround the yolk of the egg 

 the secretion of the membranes and shell begins. This 

 will be noted at the lower end of the oviduct canal. This 

 process is completed by the time the egg leaves the uterus, or 

 shell gland, whereupon it passes out through the vent. 



POULTRY FEEDS AND THEIR BY-PRODUCTS 

 Poultry should have that kind and variety of food 



which would be natural in the environment of fowls on range. 



It may be supplemented or modified, however, by such 



feeds or methods of feeding as experiment and experience 



may have found productive and profitable. 



Grain feeds. The principal feeds fed to poultry consist 



