34 



Constants calculated from Table 11. 



Sires' hatchability mean 

 Sires' hatchability standard deviation 

 Sires' daughters' mean hatchability . 

 Sires' daughters' standard deviation 

 Coefficient of correlation 



.6824±. 004084 

 .1229 ±.002888 

 ,6753±. 006217 

 .1868±. 004396 

 .2268zt .031523 



The mean hatchabihty of the sires is almost identical with that of the daughters. 

 This is in striking contrast to the mean of dams and daughters given in table 5 

 where the figures are .7064±. 003891 and .5091 ±.003740, respectively. Such 

 evidence might be interpreted as showing that a closer relationship exists between 

 sires and daughters than between dams and daughters in hatching power. Such a 

 relationship is probably due entirely to the somewhat dissimilar methods for meas- 

 uring hatching power in sire and dam. The range of variabihty is greater in daugh- 

 ters than in sires evidently because of the variable nature of the males mated to 

 these daughters. 



The coefficient of correlation between sires and daughters is .2268±. 031523. 

 Comparing this factor with the factor calculated from table 5 where mothers and 

 daughters are concerned, the two are found to be of almost identical magnitude 

 when their probable errors are considered. Table 11 furnishes convincing evi- 

 dence of the heritability of hatching power. In this instance, hatching power of 

 sires is carried on in their daughters. Table 11 further points to the necessity of 

 using tested males in developing a flock carrying uniformly high hatching power. 



Section 12. Relation of Sire's Dam to his Daughters' Fertility. 

 In section 8 the relation between sire's dam and his phenotypical fertiUzing 

 ability has been considered. A negative relationship was found to exist in that 

 case. The present section is an attempt to discover if the sire transmits to his 

 daughters a degree of fertility similar to that of his dam, so that when these 

 daughters are mated with other males their probable fertility may be forecasted. 

 In table 12, 748 pullet fertility records are tabulated with the fertiUty records 

 of their sire's mother as a pullet. 



