66 



TECHNICAL BULLETIX 7 



Coefficient of correlation 



.2358 z= .0135 



The magnitude of the above constant points to a linkage between broodiness 

 and high winter intensity. Herein lies a probable explanation why the heavier 

 l)reeds, all of which carry the broody trait, are in general superior winter 

 layers to the non-broody lighter breeds. In the liistory of the flock under 

 consideration, the highest average winter records, 67.65 and 74.5 eggs, were 

 made by the 1920 and 1921 flocks with a percentage of broodiness amounting 

 to 46.03 and 44.56 respectively of birds included. The 1923 flock, for example, 

 showed 27.35 per cent broody and a mean winter egg record of but 51.04. 

 Probably broody birds carrying early sexual maturity and no winter pause are 

 superior as winter layers to non-broody birds possessing the same two traits, 

 because of some linkage between broodiness and high intensity. Further 

 consideration is given to this important question in sections 9 and 10. 



9. Correlation Between the Presence of Broodiness and Winter Rate above 

 the Mean of Broodies and Non-broodies Combined — Pullet Year (Unimproved 

 Flock 1916). 



Winter rate and broody records are complete for 332 birds in the 1916 flock. 

 These have been correlated below: 



Coefficient of correlation 



.4770 it .0286 



This is a rather pronounced correlation and siiows winter intensity was 

 associated with broodiness in an early flock. 



10. Correlation Between the Presence of Broodiness and Winter Rate above 

 the Mean of Broodies and Xon-Broodies Combined — Pullet Year (Improved 

 Flock 1923). 



Winter rate and broody records for 430 birds hatched in 1923 are tabulated 

 below : 



