BROODINESS AND FECUNDITY IN FOWL 67 



Coefficient of correlation -j- .2925 ± .0297 



A .significant coefficient of correlation between broodiness and high winter 

 rate suggests that there is linkage between broodiness and high winter in- 

 tensity. Further evidence has already been presented in sections 8 and 9. 

 Herein lies the probable superiority of broody breeds over non-broody breeds 

 in winter intensity. 



11. CorreUition Beticeen Times Broody and Annual Rate — Pullet Year. 



Tlie uicthod used in calculating annual rate does not allow for winter pause 

 or for time lost while broody. It is simply a figure intended to measure the 

 actual rate of laying between the time of laying the first pullet egg, and time 

 of laying the last egg before the complete molt. Winter pause birds and 

 broody birds are actually penalized in calculating annual rate. If there is 

 al)Solute independence between broodiness and winter pause, the only normal 

 handicap that the broody bird carries over the non-broody is the production 

 loss during broody periods. Inasmuch as the magnitude of the annual rate 

 depends most largely upon yearly egg production, this method of measuring 

 rate should be most significant in breeding for fecundity. It is believed that 

 this is a true measure of actual rate of laying during the year. Constants 

 calculated from the 2245 individuals studied follow: — 



Xuniher of birds ....... 2245 



Mean times broody ...... 1.44 



Times broody standard deviation . . . ±1.98 



Mean annual rate . 56.48 



Annual rate standard deviation .... ±9.85 



Coefficient of correlation —.2620 ± .0133 



The above constants show that the 2245 birds actually laid on 56.48 per 

 cent of the possible days between their first egg and the time they ended 

 tlieir year with the complete molt. The standard deviation agrees closely with 

 tiiat for the winter rate. A mean rate of such a magnitude immediately 

 suggests high annual production. 



The coefficient of correlation between times broody and annual rate is nega- 

 tive; and its magnitude, together with its small probable error, suggests that 

 l)roodiness and low rate tend to move together. 



B\' the use of the regression coefficient we find that those birds with a 

 mean rate of 60.48 will be less broody than the mean of all birds studied 



(144 .21 = 1.23). The fact is very evident, therefore, that liroodiness tends 



to lower annual rate of laying. The coefficient as determined, however, does 

 not represent the true correlation, since the flrick of 2245 birds is made up of 

 h(itli broodv :ind non-broody races. 



