No. 614] 



EGG PRODUCTION 



77 



off more gradually than the left. The mean has a value 

 of 261.18 days. 2 



The curve for the flock of 1915-16 (Fig. 1) is somewhat 

 unlike the preceding. It is distinctly bimodal, but it is 

 not altogether clear that this bimodality indicates two 

 genotypes, for it may be due to chance alone. The base 

 is broader than for the 1913-14 curve, indicating less 

 homogeneity of the flock in this respect, although the 

 same gradual slope on the right-hand side is apparent. 

 There are reasons, however, for believing that the left- 

 hand side of the graph for the flock of 1913-14 was short- 

 ened by the methods of handling the pullets that fall. 

 The mean has a value of 263.18 days. The difference be- 

 tween this graph and the first is undoubtedly due to the 

 changes in the composition of the flock as described in an 

 earlier paragraph. 



Graphic representations of the day on which the vari- 

 ous members of the flock produced their first egg are 

 shown in Figs. 5 and 6. The data for the two flocks, i. e., 

 1913-14 and 1915-16, are divided into groups according 

 to the month in which the pullets were hatched. Each 

 dot in the figure represents the first egg of a pullet 

 and is placed in a square corresponding to the date on 

 which the egg was laid. If more than one pullet began 

 to lay on a given date, there is a dot for each pullet. 



There are some interesting differences and resem- 

 blances between the groups mentioned in the distribution 

 of the first egg through the various months. In all in- 

 stances the pullets laying for the first time come in slowly 

 during the first few weeks. Then follows a period of six 

 to eight weeks during which the new pullets come in at 

 a faster and fairly uniform rate. This period is followed 

 by a third period when new pullets come in slowly, the 

 last of the period representing the stragglers. The fairly 

 uniform seatter is due in part to the inclusion of several 



