ANNUAL MOLT IN R. L REDS 19 



The biological laying year terminated about September 27 in the earlier group, 

 compared with October 20 for the later group. An average persistency three 

 weeks longer in the later molting group had a very significant effect on the number 

 of eggs laid. 



Production during the Biological Year in Relation to Wing Molt. — It is de- 

 sirable to know whether the number of weeks spent in shedding the primary 

 wing feathers is associated with the number of eggs laid during the biological 

 year. In other words, is rapid molting advantageous from the standpoint of 

 egg production? Table 11 presents the data on 135 production-bred females. 



Table 11. — Duration of Wing Molt and Egg Production During 

 THE Biological Year, Production Stock Only, 1939-1944. 



2 



4 



6 1 207.0 



8 2 264.5 



10 9 238.6 



12 12 230.2 



14 11 234.9 



16 24 230.2 



18 23 234.0 



20 16 223.8 



22 29 228.3 



24 8 180.4 



There was a wide range in the number of weeks required to shed the ten primary 

 wing feathers. The shortest period observed was six weeks, and the longest 24 

 weeks. The most common period was 16 to 18 weeks. No association was ob- 

 served between the duration of wing molt and antecedent egg production. 



All females in seven generations of the production-bred stock have been tab- 

 ulated to study date of onset and date of completion of wing primary molt in 

 relation to the number of eggs laid during the first biological year. Since a 

 considerable number of these birds began their wing molt before August 1, no 

 record was secured on when they began. Records for date of onset are available 

 on 175 out of a total of 277. These 175 birds are divided into complete and in- 

 complete molt groups in table 12. 



The onset of wing molt occurred slightly earlier on the average in the group of 

 birds that finished this molt by the end of December than in the group finishing 

 later. There is considerable evidence that late onset of molt is likely to be pre- 

 ceded by high egg production. 



Late completion of wing primary molt again appears to be a good criterion of 

 high antecedent egg production. In the population with complete wing molt by 

 the end of December, the majority of the birds terminated their molt in Novem- 

 ber and December; but only about 49 percent of the 277 females studied had 

 completed the wing primary molt by January 1. 



