144 



POULTRY PRODUCTION 



those inrlividiials which molt late in the fall also lay late and 

 usually lay more eggs during the year than the early niolters. 

 It is of course the female which combines the most of the 

 favorable factors mentioned above which makes the greatest 

 layer, other things being equal. 



In sjiite of the great complexity of the ])roblem, as the result 

 of studies involving thirteen generations and several thousand 

 individuals of the Barred Plymouth liock breed, Pearl' was 

 able to reach rather definite conclusions concerning the 

 result of selecting for egg production. 



Fi.i. 70 



Showing the difference in Ijarring of Plymouth Rocks that are full brother 

 and sister. (Courtesy of Kansas Agricultural Experiment Station.) 



He proved first of all that high egg production is just as 

 much a heritable character as the tjY>e of the comb or the 

 color of the feathers. His results were of such a nature 

 however, that he was forced to conclude that in the Barred 

 Plymouth Pock breed a pullet can inherit the powers of high 

 ]irodnction from her sire only, a type of inlieritance referred 

 to as sex-linked. 



The most familiar example of this type of inheritance in 

 poultry and one which may aid in understanding the wav in 



1 Maine Bulletin, Ko. 205. 



