144 MAINE AGRICUI^TURAI, EiXP^RIMENT STATION. I909. 



TABI.E: XXIII. 



Comparison of Fathers' Average Pen Records of Infertility and 

 Hatching of Bggs, zvith the same Characters in their 

 Daughters. 



Cockerel 

 number. 



Average per cent, 

 of infertile eggs 

 shown by females 

 loated with the 

 male designated. 

 (Father's pen 

 average infer- 

 tility.) 



Average per cent. 



of infertile eggs 



shown by the 



daughters of the 



designated male. 



Average per cent. 



of fertile eggs 

 hatched shown by 

 female mated with 

 designated male. 



(Father's pen 

 average of hatch- 

 ing quality. 



Average per cent. 



of fertile eggs 

 hatched shown by 

 the daughters of 



the desia;nated 

 male. 



D 31 



8.9 



9.7 



46.0 



41.2 



D 32 



16.7 







44.3 



61.0 



D 60 



19.2 



6.3 



26.4 



38.3 



D 17 



20.3 



1.0 



41.4 



70.0 



D 65 



20.6 



10.7 



31.4 



65.0 



D 26 



20.8 



78.0 



50.3 



76.5 



D 35 



21.0 



16.5 



32.1 



44.3 



D 11 



22.4 



49.6 



33.8 



40.5 



D 70 



22.5 



6.0 



36.5 



60.1 



D 16 



23.0 



1.8 



24.6 



54.7 



D 68 



26.0 



13.1 



48.2 



40.7 



D 5 



26.6 



7.7 



26.2 



33.0 ■ 



D 56 



27.0 



3.0 



25.6 



35.0 



D 61 



29.0 



25.2 



31.4 



38.4 



D 57 



34.8 



10.0 



34.2 



36.2 



laid by all the birds in the pen headed by each cockerels. Pro- 

 vided sufficiently large numbers of females are used with each 

 male in a breeding pen so that it may be supposed that they 

 give a fair random sample of breeding females in general, the 

 average fertility and hatching quality of eggs from the pen 

 through the whole season may be taken as in some degree a 

 measure of that particular male bird's breeding ability. 

 Assuming that the females represent average samples, 

 differences in the average fertility and hatching quality 

 of the eggs from different pens may be attributed to innate 

 differences in the breeding ability of the cockerels, always 

 provided other conditions are kept the same. Now this ques- 

 tion may be raised : What is the degree of correlation existing 

 between a male bird's average pen fertility of eggs (such as is 



