14 



MASS. EXPERIMENT STATION BULLETIN 429 



Early molting has long been thought to be inimical to high egg production dur- 

 ing the first laying year. The date of onset of wing pri.mary .molt was recorded 

 for all birds that had not molted any wing primaries by the end of July when 

 observations began. Of the 33 exhibition females studied, only 22 began their 

 wing molt after the first of August, and of the 277 production females, 175 began 

 the wing molt after August 1. The date of onset of wing primary molt was there- 

 fore determined for only about two-thirds of the females. 



The time of completion of winy primary molt was recorded if it occurred before 

 January 1. If wing molt was not complete when observations stopped at the end 

 of December, such individuals were placed in the "incomplete molt" group. 



The mean number of eggs laid in the biological laying year was recorded for 

 each group. 



The data are presented in table 6. 



Table 6. — Rel.\tion Between Month of Onset and Completion 

 OF Wing Primary Molt and Egg Production During Biological Year. 



.Aug. Sept. 



Oct. 



Jan. 



Complete Wing Molt 



Exhibition Stock 

 Onset of wing molt 



Number of birds S 5 



Average production during 



biological year, eggs 175.8 173.6 



Completion of wing molt 



Number of birds 



Average production during 



biological year, eggs 



Production Stock 

 Onset of wing molt 



Number of birds 



Average production during 

 biological year. eggs. . . 

 Completion of wing molt 



Number of birds 



Average production during 

 biological year, eggs. . . 



180.9 



191.0 



185.3 



5 6 



197.6 253.3 



1 1 29 26 14 



224.0 204.0 219.1 228.0 236.9 



Incomplete Wing Molt 



Exhibition Stock 

 Onset of wing molt 



Number of birds 1 2 



Average production during 



biological year, eggs 208.0 244.5 



Production Stock 

 Onset of wing molt 



Number of birds 



Average production during 

 biological year, eggs. . . 



13 II 2 



235.4 26S.7 249.0 



The data indicate that females that complete their wing primary molt b}- the 

 end of December usually begin their wing molt earlier than those that have not 

 completed wing molt by January 1. 



In the exhibition stock there is no evidence in the limited data that time of 

 onset of wing primary molt affects the number of eggs laid during the biological 

 laying year. In the group of production-bred females with complete wing molt, 



