INBREEDING IN RELATION TO EGG PRODUCTION 295 



In body weight at first egg the inbred mothers increased from the initial mean 

 of 4.81 pounds to 5.72 pounds in 1925. The check mothers began with a mean 

 weight of 5.45 pounds and increased to a mean of 7.24 pounds in 1925. The 

 inbred daughters averaged 5.81 pounds the first year, and their average was 5.61 

 pounds in 1925. The check daughters averaged 6.23 pounds in 1923, 6.68 

 pounds in 1924, and 5.81 pounds in 1925. The chart therefore indicates that 

 even though the mean weight of mothers selected each year was increased, their 

 daughters in both groups decreased in mean weight at first egg. 



During the last three years of the experiment there was a close correlation in 

 body weight between mothers and daughters. In 1926 the check daughters 

 averaged 5.68 pounds at first egg, and in 1928 their mean weight was 5.55 poimds. 

 Inbred daughters in 1926 averaged 5.76 pounds and in 1928, 5.23 pounds. Check 

 daughters still remained heavier than inbred daughters even after three years of 

 inbreeding. In view of the fact that the foundation hen of all inbred hues 

 (C 1124), weighed but 4.81 pounds at first egg, the inbred group has behaved as 

 might be anticipated. The check group, however, has shown a sUght dechne 

 in weight from inbreeding as compared with crossbreeding. 



100 



90 



80 



70 

 60 



50 

 u-o 

 30 



20 



niBRSD DAMS 

 CHECK DAMS 

 INBREB DAU0HTES3 

 CHECK DAUGHTERS 



igaM. 1925 • 1926 19< 



BATING YEARS 

 CHART 3. — Effect of Inbreeding on Winter Pause 



192« 



Chart 3 presents the percentage of non-pause mothers and daughters through- 

 out the experiment. In the beginning there were no non-pause mothers chosen 

 for the inbred group. In 1924, 43 per cent of the inbred mothers producing 

 daughters lacked winter pause. In 1925 all inbred mothers again showed winter 

 pause. All check mothers with daughters up to 1925 carried winter pause. 



Inbred daughters from the 1923 matings gave 33 per cent non-pause. For 1924 

 the percentage had risen to 40. In 1925 all inbred daughters exhibited winter 

 pause. Check daughters of 1923 showed 20 per cent free from pause; in 1924 

 there was an increase to 50 pe" cent; and in 1925 the check daughters, like the 

 inbred daughters, all showed winter pause. Inbreeding has not intensified 

 winter pause because both inbred daughters and check daughters closely agree in 

 the three years in question. 



When the plan of matings was changed in 1926, all inbred mothers from 

 which progeny were retained showed winter pause. In 1927, 20 per cent of the 

 inbred mothers were free from pause. In 1928, 38 per cent of inbred mothers 

 lacked winter pause. All of the check mothers of 1926 carried winter pause. 



