36 



Table 13. — Correlation in Hatchability hetiveen Sires' Dams and Sires' Daughters. 



Constants calculated from Table 13. 



Sires' Dams' Mean Hatchability 

 Sires' Dams' Standard Deviation 

 Sires' Daughters' Mean Hatchability 

 Sires' Daughters' Standard Deviation 

 Coefficient of Correlation . 



.70 19 ±,004664 

 .1891 ±.003298 

 .5096 ±.007588 

 .3077 ±005366 

 .0588 ±.024576 



The mean hatching power of the hens whose sons were used for breeding was 

 .7019. The daughters of this group of males averaged only .5096 of fertile eggs 

 hatched. This difference in the means amounts to .1923 ±.008906 and is a much 

 more striking difference than was observed between the same group of females in 

 fertility. The standard deviation of the two groups agrees with that found for 

 fertility in table 12. Again the daughters of the males show almost double the range 

 in variability of their sires' dams. 



The coefficient of correlation is here positive, but of no significance since it is 

 a httle more than twice its probable error. The lack of correlation between sire's 

 dam and sire's daughters in hatchability can scarcely be interpreted to show that 

 hatchability is not governed by factors transmitted from sire to daughter. The 

 hatching power of a cockerel's dam is only the phenotypical manifestation of her 

 ability and may be affected by her mate as well as by numerous environmental 

 factors. She furnishes, moreover, but a part of the heritage of her son. If several 

 factors governing hatchability are transmitted equally by males and females and 

 if both parents have an influence on the hatching power of eggs laid and fertilized, 

 respectively, this apparent independence of hatching power in inheritance will be 

 explained. 



