8 . MASS. EXPERIMENT STATION BULLETIN 359 



Table 3. — The Behavior of Fertility from the Standpoint of the Males 

 (Omitting Outbreds and Inbreds) 



Number 



of 

 Males 



Percentage 

 of Fertile 

 Matings 



Percentage of Males 



with 61 percent 

 Fertility or Higher 



Late Group 



1922 17 98.85 



1923 22 86.85 



1924 27 92.14 



1925 27 89.92 



1927 23 91.35 



1928 29 93.46 



1929 24 88.10 



1930 21 94.07 



1931 , 19 94 62 



1932 19 93.33 



Early Croup 



1933 20 90.80 



1934 20 84.62 



1935 21 84.18 



1936 16 82.84 



Total and means 305 90 . 37 



77.29 



Results from Changing Males 



When breeding females continue to lay infertile eggs during the breeding season, 

 a common practice is to mate to a different male. The prevalence of such females 

 in the flock and the efTectiveness of such a procedure has been studied. The 

 data are presented in Table 4. 



Table 4. — Change of Male as Affecting Fertility 



In the late-hatched group 1,237 females were included. Of this number 3.23 

 percent remained infertile throughout the breeding season when mated to one 



