48 I 



THE AMERICAN NATURALIST 



[Vol. L 



bodily conditions familiar to poultrymen as indications of 

 the attainment of maturity. These conditions may be ob- 

 served in the male as well as in the female. There is also 

 an apparent tendency on the average for large pullets to 

 make lower records than their smaller sisters, as shown 

 by the negative correlation between high winter egg pro- 

 duction and large size, due probably to a longer growth 

 period in the larger pullets. 



The relation between age at first egg and rate involves 

 the following points : A pullet that matures late can not 

 give expression to high fecundity, although she may carry 

 the genes for it, but the record of a pullet that matures 

 fairly early will depend upon the rate at which she lays. 

 On the other hand, a zero producer will be also late ma- 

 turing, judged according to the criterion suggested, be- 

 cause she does not lay until spring, provided, of course, 

 that she was hatched at the proper season. It is obvious 

 of course that a high record bird must mature early in 

 order to make her record, and that in this sense early 

 maturity and high productiveness will go hand in hand, 

 but early maturity of itself does not insure a high record, 

 for early maturing birds may lay poorly and so make a 

 low record. On the other hand, late maturity is bound to 

 insure a relatively low record. In the flock of Reds with 

 which we have had to do there is comparatively little dif- 

 ference in the rate of production. In one flock the coeffi- 

 cient of correlation for the time elapsing between the first 

 egg and the 1st of March and the number of eggs laid was 

 calculated and found to have a value of .8612 =4= .0132 

 which must mean that the flock was fairly homogeneous in 

 respect to rate of production. In other flocks there is 

 clearly a negative correlation between age at first egg and 

 winter egg production but the values have not yet been 

 determined. The difference between a pullet that begins 

 to lay December 1 and lays 60 eggs, another the first of 

 J anuary and lays 40 eggs, another that begins the first of 

 February and lays 20 eggs, must be a question of start. 

 The last bird, too, must be essentially different from a 



