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THE AMERICAN NATURALIST [Vol.LII 



duced by broodiness, but that the hens are broken up so 

 quickly and the impulse toward resumption of egg pro- 

 duction at this season is so strong that it inhibits the 

 moult at various stages. 



Pullets that begin to lay very early in the fall very 

 often undergo a moult during the latter part of the same 

 fall. It is not clear that early production of itself tends 

 to induce the moult so long as the birds affected are not 

 hatched too early in the season. The moult is more com- 

 monly observed in pullets that are hatched very early in 

 the season and which begin to lay in August and Septem- 

 ber. Such birds rarely make a continuous record but in- 

 stead stop laying after producing a variable number of 

 eggs and moult much like birds from fifteen to eighteen 

 months of age. In the flocks with which we have been 

 dealing the variability in maturity has induced some com- 

 plications in handling the flocks. If an attempt is made 

 to hatch birds sufficiently early in the season, so that a 

 good share of them will begin laying in November, some 

 begin too early, lay a while, and then moult. 



Rate and Rhythm of Production. — The percentage rate 

 of production at any time and for any period may be 

 taken as the number of eggs times 100, divided by the 

 length of the period involved, measured in days. Rate 

 is an important factor in determining egg production, 

 but in the Rhode Island Reds is of quite secondary im- 

 portance as compared to date of first egg (and of course 

 age at first egg). 



The distribution of the percentage rate calculated for 

 the winter period (between the first egg of each pullet 

 and March 1) for the flock of 1913-14 has been deter- 

 mined and the graph shown in Fig. 10 plotted. The 

 curve shows a considerable homogeneity of rate in the 

 flock. Since the general trend of events, such as acci- 

 dents, temporary ailments, etc., is of such a nature that 

 some birds do not attain their natural inherent rate, the 

 curve shows a very gradual slope at the left-hand side up 

 to about 30 per cent., a somewhat more rapid rise be- 



