nR()()i>iNKss AND i'K( rxnnv i\ fowi. 



77 



.'(.'. Vorreltidon Hcticeeii tin Presence of Broodiness and ]\'inler Production 

 (il'ove the Mean of Brood'ux and Xon-broodies Combined— Pullet )'fiir ( I m- 

 /.rni-ed Flock IV2S). 



Coefficient of correlation + .1563 ±: .0317 



This constant is of questionable magnitude and signilies tliat winter produc- 

 tion of the 1923 flock above the mean of 53.62 eggs is but little dependent 

 upon the presence of the broody trait. The fact should be recalled, however, 

 that the maxinnmi winter production (74.5 eggs) was made by the 1921 flock 

 with 44.56 per cent of the birds broody during the pullet year. 



The later sections of this report are devoted to a consideration of the cor- 

 relation between rate and egg yield and broodiness and egg yield. 



J7. Correlation Betxceen Winter Rate and Annual Eyy Production — Pullet 

 Year. 



In commercial poultry breeding for fecundity, a short-time measure of 

 probable annual production is of vast importance. If the winter rate could 

 be used as a l)asis for selecting breeding females as efficiently as the yearly 

 record, it would be of vast economic importance. By making use of the co- 

 efficient of correlation, a measure of the probable worth of tlie winter rate in 

 selecting for large yearly records is obtained. The constants arrived at in 

 this study are given below: — 



Xiuiiber of birds .... 



.Mean winter rate 



Winter rate standard deviation . 



Mean annual production 



.\nnual production standard deviation 



Coefficient of correlation 



2242 



66.41 



±9.38 



174.37 



±44.59 



+.4561 ± .0113 



The mean annual egg production of the 2242 birds used in section 27 was 

 174.37, with a standard deviation of 44.59, or a coefficient of variation of 

 about 25 per cent. The class range in egg production is from 21 to 300 with 

 class intervals of 10. This wide range in production is due to the hetero- 

 ireneitv of the flock and to the number of characteristics that affect production. 



The magnitude of the correlation coefficient, together witli the small ])roi)- 

 ahle error, suggests that winter rate is rather intimately correlated with 

 annual esift production. 



,'cS. Correlation Beticeen Annual Rate and Annual E</(j Yield. 



Annual rate as calculated for this flock is a rather concise measure of in- 



