10 MASS. EXPERIMENT STATION BULLETIN 301 



The data show that the non-broody line gave higher winter egg production 

 throughout the experiment. By Fisher's method, the two series of nine mean 

 winter records differ significantly. The weighted means for the nine-year period 

 are also significantly different. In this experiment the non-broody line gave a 

 winter egg production more than twelve eggs greater than the broody line. 



Table 10. Winter Egg Production in Non- Broody and Broody Lines. 



11. Annual Egg Production 



Annual egg records represent the number of eggs laid by each individual from 

 her first pullet egg to a date .^65 days later. In this experiment the two lines are 

 considered first as made up of broody and non-broody individuals and second as 

 entire populations. As stated earlier in this report, the attempt is being made to 

 develop the two lines for similarity in all characters except broodiness. In section 

 3, however, the two lines are shown to differ in winter pause. In age at first egg, 

 winter clutch size, and persistency the two lines do not differ significantly. Table 

 11 presents the condensed data. 



Both lines were made up of broody and non-broody individuals in the pullet 

 laying year. The 194 non-broody individuals in the non-broody line averaged 

 212.21+2.01 eggs per year for the experimental period, compared with 184.94 

 +3.08 eggs for the 53 non-broody birds in the broody line. This is a significant 

 difference and indicates that the two lines differed in their egg-laying ability aside 

 from degree of broodiness. 



Consitlering the broody individuals in the two lines, 73 in the non-broody line 

 averaged 203.41+2.94 eggs compared with 177.50+^1.48 for the 206 birds in the 

 broody line. In the case of these two groups of birds, the difference in mean annual 

 production may be attributed in large part to differences in degree of broodiness. 



When all birds in the two lines are considered, the data show that the mean 

 annual egg production of the non-broody line excelled that of the broody line in 

 every year reported. The mean for the entire experimental period for the 267 

 birds in the non-broody line was 209.81+^1.67 and for the 259 birds in the broody 

 line, 179.02 + 1.34. The actual dilTerence in this case was 30.79+2.14 eggs. By 

 Fisher's method, the probability of obtaining chance differences in annual egg 

 production as great as those reported in the nine-year period is zero. The data 

 clearly indicate that the non-broody line was distinctly superior to the broody 

 line from the standpoint of annual egg production. 



