26 



Constants calculated from Table 5. 



Dams' mean hatchability 7064±. 003891 



Dams' standard deviation 1643±. 002752 



Daughters' mean hatchability 5091 ±.007340 



Daughters' standard deviation 3099±. 005190 



Coefficient of correlation 1960±. 022805 



Table 5 undoubtedly shows that hatching power is transmitted from mother to 

 daughter, yet while the dam's mean hatchabihty is .7064, her daughter's mean was 

 only .5091. The standard deviation of dams was .1643 and their daughters' 

 standard deviation was .3099. Thus the range of variation in daughters as meas- 

 ured by the magnitude of their standard deviation is almost double that of their 

 dams. Such would be the case if a dominant factor is present for high hatcha- 

 bility. This relative variability is in exact agreement with the same observation 

 on fertility as pointed out in section 4. 



There is a positive correlation coefficient of .1960±. 022805 between dams and 

 daughters in hatchabihty. During the progress of the experiment, the pullet 

 breeders used on successive years came from pullet mothers that showed a good 

 hatching percentage. In other words, the pullets that were used as breeders in any 

 one year came from pullet dams that had laid eggs of good hatching power. 

 According to Pearson ('03) rigid selection in parents may reduce the correlation 

 between parent and offspring for the character in question. Since we have no fer- 

 tihty and hatchability records for the flock as a whole, it is impossible to mathe- 

 matically measure the effect of such selection on our flock. 



