402 COMMERCIAL POULTRY RAISING 



Size. — ^Although certain breeds are credited with laying larger 

 eggs than others, as a general rule the size of an egg is controlled 

 principally by selection of layers of large eggs and judicious 

 breeding toward this end. In a number of tests conducted by 

 Experiment Stations it has been found that care and feeding 

 have slight influences in the sizes of eggs, but this does not estab- 

 lish anything beyond the fact that the condition and general 

 health of the fowls are directly responsible. At the beginning of 

 their laying period pullets lay a much smaller egg than those laid 

 during the height of their laying season. Similarly, as a hen 

 approaches the molt, her eggs become smaller. The difference in 

 food value per pound is in favor of the large eggs, because they 

 liave a smaller percentage of shell. 



Food Value. — It should be borne in mind, however, that there 

 is considerable difference in the food value of eggs of different 

 grades. Furthermore, the season of the year has something to 

 do with the quality of eggs. Those produced in summer are of 

 lower quality; the albumen is more watery than the eggs pro- 

 duced in the spring, hence they are not so desirable for storage 

 purposes. In candling, the yolks of summer eggs float lower in 

 the albumen, which is a sign of weakness, and the yolks appear 

 slightly darker than in spring eggs. Packing houses always aim 

 to store eggs produced during March, April and May for best 

 results. 



It is almost certain that some hens have an inherited tendency 

 to produce eggs of poor quality, for the same reason that certain 

 hens will almost invariably lay a malformed egg. If this is true, 

 it is reasonable to suppose that this characteristic will descend 

 to their progeny. Flocks sh'ould be culled for the quality of their 

 eggs as well as for their productiveness. In no other way is it 

 possible to develop a flock that will lay a uniformly high grade of 

 eggs. 



Abnormal Eggs. — ^To further illustrate the remark that a 

 newly laid egg is not ajavays a desirable egg, some of the most 

 common abnormalities will be discussed. Double-yolk eggs 

 result from the joining together of two yolk sacs during their de- 



