232 W. V. LAMBERT AND C. W. KNOX. 



Both the high and low sex ratios appear in colonies of White 

 Leghorns. The individual range in the colony showing the 

 lowest per cent, of males was from 33.3 to 66.7 per cent. In the 

 colony showing the highest sex ratio the range was from 44.4 to 

 85.7 per cent. In tabulating this range only birds producing ten 

 or more chicks and embryos that were sexed were included. This 

 included all individuals in the small colony and fourteen out of the 

 fifteen in the large colony. The average sex ratio in the last case 

 when determined for the fourteen birds having 10 or more sexed 

 offspring was 59.2. It was thought necessary in determining the 

 range to include only birds having ten or more sexed offspring 

 as any smaller number than that would hardly give a repre- 

 sentative sample. 



From the total of eleven colonies only three show sex ratios of 

 less than 50. No relationship appears to exist between breeds 

 and the sex ratio for the hybrids show about the same variation 

 as do the pure breeds. 



THE INFLUENCE OF EGG WEIGHT AND PRODUCTION UPON THE 



SEX RATIO. 



Jull (1924) found no relationship between average weight of 

 eggs and the sex ratio, and Jull and Quinn (1925) found no cor- 

 relation between the weights of individual eggs and the chicks 

 hatching from them. 



Since the average egg weights for all FI hens used in this 

 experiment were available as well as the sex ratio for these hens, 

 a correlation between these two variables has been calculated. 

 In this study only those hens that have a total of ten or more 

 chicks or embryos upon which the sex had been determined were 

 included, the total number being thirty-nine. The correlation 

 coefficient for egg weight and percentage of males was - - 0.060 

 db 0.108. This correlation being smaller than its probable error 

 certainly indicates that no direct relationship exists between 

 these variables. 



On this same group of FI birds the rate of production preceding 

 the hatching season has not influenced the sex ratio. In this 

 calculation the percentage rate of production was used. This 

 rate of production was used because the birds began laying at 



