no POULTRY PRODUCTION 



was separated from the male so that no further matings 

 were possible. 



The shortest time after mating in which fertile eggs were 

 produced was forty-two hours (Nos. 38 and 351). Hens 

 309 and 403 laid sterile eggs forty-eight and forty-six hours 

 respectively after mating. These were the only cases that 

 the first egg laid forty-two hours or more after mating was 

 not fertile. 



Judging from common experience in addition to the fore- 

 going, it seems safe to state that in practice it will be found 

 that eggs laid by vigorous hens will usually be fairly fertile 

 in six days in the case of Mediterranean breeds, and eight 

 to ten days in the case of the American breeds, while two 

 weeks is necessary in the case of pullets, assuming in each 

 case that the male is vigorous and active. 



Cessation of Fertility. — In experiments with twenty Single 

 Comb White Leghorn hens, Waite^ found that fertility 

 held up well for eleven days, and one egg was found to be 

 fertile after the male bird had been removed for twenty 

 days. Bittenbender^ reports a Barred Plymouth Rock hen 

 that produced a fertile egg seventeen days after the removal 

 of the male. 



Sherwood' reports one Barred Plymouth Rock- hen that 

 produced one fertile egg on the twentieth day after the mating 

 was broken up; four White Leghorn pullets that produced 

 fertile eggs on the nineteenth day; two Leghorn hens that 

 laid fertile eggs on the eighteenth day after the male bird 

 was removed. He found that the fertility held up well with 

 the Plymouth Rock hens for twelve days, while the Leghorn 

 pullets' eggs decreased markedly in fertility on the tenth 

 day, as did also those of the Leghorn hens. 



After the end of the third week, according to Lillie,* the 

 vitality of the spermatozoa is reduced. Eggs laid during, 

 the fourth and fifth week after the removal of the male 

 may exhibit an abnormal cell division, which soon ceases. 



' Maryland Bulletin No. 157. 



' Unpublished data, Iowa State College. 



" Ibid., Ohio Experiment Station. 



* Development of the Chick, 



