BREEDING FOR EGG PRODUCTION. 8l 



producing capacity of eggs, and that the assumption of uniform I 



fertility in the eggs of each hen for considerable periods of time 

 was not sustained. 



In the table on pages 82 and 83 there is given, in addition to the 

 egg yield of 76 hens, an incubation test of the eggs laid during 

 the last 10 days of May, 1902. ;, 



The data show plainly the great variability in the fertility of f 



the total egg yield of different hens ; some birds yielding eggs 

 that are all highly fertile, and others giving eggs that are all 1: 



completely infertile, being as clear after 21 days of incubation f 



as at the start. Again some hens are very irregular in the 

 fertility of their eggs ; an egg laid one day yielding a chick, 

 while that laid on the next is completely infertile; or they are 

 fertile for a day or two, or more, and then infertile, becoming 

 fertile again after one, two, or more eggs are laid. This seems 

 to be true with some individuals, whether they are laying reg- 

 ularly or irregularly, or- whether they have been laying a long 

 or a short time. The eggs from other hens seem to be slightly 11 



fertile, the embryo dying before the tenth or twelfth days. This f 



appears to be regular wuth some hens, and irregular with others ; 

 as some give eggs of low fertility one day and high fertility on 

 the days immediately following, or preceaing. 



The results given in the table plainly show the great variability 

 in fertility. For instance; the egg of the first hen on the list. 

 No. 511, was laid May 21st, and it stopped developing about the 

 tenth day of incubation. The next one was laid May 24th and 

 it yielded a good chick. Both eggs were in the same incubator, 

 on the same shelf, where there is every reason for believing that 

 the conditions were alike. The next egg was laid by the same 

 hen two days later — ]\Iay 26th — and the germ died on the six- 

 teenth day of incubation. She laid an egg the next day follow- 

 ing and development stopped in it on the tenth day of incubation. 

 The next eggs were laid by her on the 29th and 30th insts. and 

 both yielded good chicks. 



During this ten days test she laid six eggs, three of w^hich 

 yielded chicks, and in three of which development stopped after 

 having advanced half the period, or more. Had these six eggs 

 been taken promiscuously and divided into two lots which were 

 treated differently, three chicks possibly might have been secured 

 from one lot, and three, half developed dead chicks, from the 



