10 



MASS. EXPERIMENT STATION BULLETIN 429 



The date of termination of the biological year is extremely important, accord- 

 ing to Lerner and Taylor (1941). In the group with complete molt (table 4), the 

 exhibition stock stopped laying on the average about September 13; the stock 

 bred for egg production, about September 25. In the group with incomplete 

 wing molt, both stocks terminated their laying year about the middle of October. 

 Late molting of primary wing feathers increased the persistency by about one 

 month. The actual time of wing molt, therefore, appears to be very important. 



Production during the Biological Year in Relation to Wing Molt. — Molting of 

 wing primaries has proved to be the most consistent and definite measure of molt- 

 ing behavior in our stock. Since the rate of molting has long been considered 

 important in relation to antecedent egg production, it seems desirable to present 

 specific data on this point. In table 5, the birds are classified with respect to 

 duration of wing molt, and the mean number of eggs laid by each group during 

 the biological year is recorded. 



In the limited number of exhibition-bred females observed, there is some evi- 

 dence that a period of molting wing primaries shorter than 14 weeks may be 

 associated with lower egg production. The same observation also holds for the 

 high-fecundity stock. Aside from this, there is no evidence in either group of 

 birds that the duration of wing molt is associated with antecedent egg production. 

 These data certainly present no evidence that a short molt period is associated 

 with high antecedent egg production. 



Table 5. — Duration of Wing Molt and Egg Production 

 During The Biological Year, 1938-1940. 



