CHAPTER XVI 

 EGG PRODUCTION 



Egg production distinguished from reproduction. Egg produc- 

 tion is a part of the process of reproduction in poultry performed by 

 the female, without association with the male, and yielding a product 

 immediately useful to man. Hens are generally used for commer- 

 cial egg production, the few eggs of other kinds of poultry occa- 

 sionally found in the markets or on tables being, as a rule, the 

 irregular surplus from flocks kept for breeding. An egg that has 

 not been fertilized, or that is deficient in fertility, may be complete 

 for man's use for food, or for any of the manufacturing processes 

 in which eggs are used. Whether those properties which make 

 quality in the egg used as food affect the quality of the chick 

 when the egg is incubated has not been determined. Presumably 

 they do, but no demonstrations have been made which show it. 

 We may profitably use for egg production hens that it is not 

 advisable to use for reproduction. Egg production is in a large 

 measure, though not wholly or regularly, under the control of the 

 poultry keeper, and may be developed to the detriment of the full 

 function of reproduction. Subjects so related cannot be wholly 

 separated for discussion or study, but as far as possible the treat- 

 ment in this chapter will avoid enlargement upon points more 

 appropriately considered in the chapters on reproduction. 



Reproductive organs of the female the source of eggs. The 

 reproductive system of the female consists of the ovaries, attached 

 to the backbone near the middle of the back, and a tube, the ovi- 

 duct, leading from the ovaries to the vent. There are two ovaries, 

 right and left, but as a rule only one is developed. Singularly, 

 the conspicuous function of the ovary is to develop the yolk, the 

 part of the egg which contributes nothing to the development of 

 the embryo, but is absorbed just before exclusion and affords 

 nourishment for the first few days. Each yolk is at first a tiny 

 globular granule. After a bird begins to lay, the ovary presents the 



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