210 THE A 31 ERR 1 A" A\ 1 T URALIST [ Vol. LII 



that the lower egg production noted after the first broody 

 period is due solely to the interruption of production. 

 During the summer, the rate of egg production slackens, 

 due almost entirely to the broody periods. The data for 

 the 1913-14 flocks show that after June the rate of pro- 

 duction . is about constant for the next three months, 

 largely because the first of July marks the point at which 

 practically every individual in the flock has entered on its 

 broody portion of the year. Some time in the late sum- 

 mer or during the fall, the various individuals stop lay- 

 ing and moult, some at one time, some at another, but 

 usually at the end of a broody period. After the rest 

 period in the fall, the birds gradually begin to lay again 

 in mid-winter, somewhat as they did as pullets, except 

 that the rate is slower as a rule. Except for this feature, 

 the character of the second year's production is much 

 the same as the first. 



The winter , cycle is regarded by the workers at the 

 Maine Station (Pearl, '12) as the most important of all the 

 cycles, at least from the standpoint of the investigation of 

 the inheritance of egg production. They have found 

 that it represents a definite period in the life history of 

 the individual, among their Barred Plymouth Kocks. 

 Furthermore, during this period, the greatest differences 

 are to be observed in the egg production among indi- 

 viduals. They also find that high winter egg production 

 is (Min elated with annual egg production, as would be ex- 

 pected except in the event that high egg production early 

 in life tends to lower production in later life. In other 

 words, a bird that is a good layer during the winter is 

 probably a good layer at all times. There are other 

 reasons, mostly of a practical nature for the use of the 

 winter cycle as a measure of fecundity. 



Taking the year as a basis the workers at the Maine 

 Station recognize as its first characteristic the winter 

 cycle beginning with the first egg of the pullet and ex- 

 tending to March 1. This date is taken as a convenient 

 working point that falls near the biological division point. 



