THE BREEDING OF CHICKENS 143 



the weatlier, fright and many others. The complexity of the 

 character itseH' has been clearly set forth by Goodale' who has 

 shown that egg production depends upon several more or less 

 independent internal factors. In order to arrive at definite 

 conclusions concerning the inlieritance of egg production, 

 each of these factors must be im'cstigated separately. The 

 factors jiointed out are, date of laying of first egg, age at lay- 

 ing of first egg, earliness of maturity, rythm and rate of 

 production, broodiness, molt and the ])crsistance <if ])roduc- 

 tion in the fall. 



Goodale- shows that for Ivhode Island Itcds the date of the 

 laying of the first egg, aside from the date of hatching, (le]icnds 

 upon the rate of growtli and the earliness of sexual maturity. 

 On the average, pullets that lay at six or seven months of age, 

 lay more eggs than those which begin laying at eight or nine 

 months or older. 



Bearing on this same ])oint, Rice^ f)fi'ers the records of 1(19 

 Single Comb White Leghorn hens, as shown in Table XX\'I 

 which indicate very marfccd correlation between early laying 

 and high pr< iduction. The four hens which l)egan to lay at an 

 age between one hundred and fifty-one and one hundred and 

 eighty days gave the largest average first year production 

 of any of the other grou]>s and also ga\-e the highest average 

 total production for a period of three years. The groups that 

 began to lay at ages between one hundred and eighty-one and 

 two hundred and and ten days and between two Inmdred and 

 eleven and two hundred and forty days gave the second and 

 third largest average ]iroduction respectively, for the first 

 year and for the three year period. 



GoodalC and others have shown that some pullets lay 

 nearly continuousy for long periods of time while others 

 which lay relatively rajiidly lay in cycles with periods of 

 rest in between. lie has also shown that broodiness tends 

 to reduce production ^•ery materially. The appearance of 

 a molt usually accompanies a break in production, while 



^ American Naturalist, \'oI. lii, Nos. 614-61S. ^ Loc. cit. 



' Cornell Countryman, vol. xii, No. 7. • Op. cit. 



