Mar. 4, i9i8 WiuieY Eqq Production of Rhode Island Reds 561 



Several features of this table require comment. First, the large per- 

 centage of the 1 91 3- 1 4 flock that falls in the zero class, and the low 

 value of the pause of maximum length. It should be noted that this 

 flock was not put into the laying houses until late October, and none of 

 them began to lay until after November i. Second, the high percentage 

 of the flocks of the April and May hatches of 191 5-1 6 and 191 6-1 7 that 

 spent practically no time at all in pauses. Thus, the sums of the first two 

 rows are 42.64 and 51 .56 percent, respectively. This high value is the more 

 remarkable for the season of 1916-17, since the birds began to lay early 

 in the fall. Contrasted with this is the third point — viz, the relatively 

 low percentage of the March-hatched pullets of these two years that fall 

 into these rows. This may perhaps be explained by the tendency of 

 March-hatched pullets to begin to lay early in the fall and to undergo 

 a winter molt.^ That the 191 3-1 4 flocks shows a radically different dis- 

 tribution is probably due to its delay in beginning production. This 

 raises the question as to whether or not the time a bird begins to lay 

 may not have a considerable effect on the appearance or nonappearance 

 of the winter pause. The individual records, however, prove that no 

 necessary relation of the sort postulated exists. 



B. RATE OF PRODUCTION 



VALUE OF MONTHLY EGG PRODUCTION AS AN INDEX OP A WINTER CYCLE 



A cycle in egg production may be indicated by a lessened daily rate 

 of production as well as by a pause. Specifically one would expect of 

 the winter cycle, if it were delineated only by a change in rate, either 

 that production should begin at a relatively high rate to be followed 

 during the latter part of the winter by a period of lessened production 

 or that the production should start at a slow rate, rise to a maximum, and 

 then decline. Following Pearl, we should anticipate that February 

 would have less eggs than January. 



In handling the data given in Tables VII to XI we have proceeded as 

 follows, unless otherwise specified. Each lot of Rhode Island Reds is a 

 group of individuals selected for the following reasons: (i) A laying 

 period of considerable length in order that ample time should be allowed 

 for the completion of the entire cycle — that is, both egg production and 

 pause. Thus, birds beginning to lay after December i are excluded from 

 the tables. (2) Records containing broody pauses are excluded. (3) 

 Each month should be equal in length. We utilize, therefore, three 

 periods of 31 days each — viz, the months of December, January, and 

 February, including in the latter the first three days of March. (4) 

 The data, furthermore, are divided into two groups — viz, March-hatched 



' Possibly the large percentage of JIarch-hatched pullets with pauses may be interpreted as being due 

 to a greater opportunity for the appearance of the winter cycle, since they begin to lay early in the season. 

 Pearl, however, does not mention an association of a molt with the winter pause. 



