ANNUAL MOLT IN R. L REDS 15 



there is no conclusive evidence that the time of onset of wing molt has any effect 

 on first-year egg production. There is some indication, however, that high first- 

 year egg production is associated with late onset of wing primary molt in the 

 birds not completing their wing molt. 



In both exhibition and { reduction stocks the number of eggs laid previous to 

 the cessation of laying associated with the first annual molt increased as the date 

 of completing wing molt advanced. In these data the date of completion ot wing 

 primary molt appears to be far more important in relation to previous egg pro- 

 duction than was the date of onset of wing primarj' molt. 



Summary of Part I 



In general, the comparison of exhibition and production stock reveals some 

 rather characteristic differences with respect to annual molt. Annual molt 

 appears to produce greater physiological effects on exhibition stock than on pro- 

 duction stock. Both exhibition males and females showed decline in body weight 

 during annual molt, while no important change was observed in production-bred 

 stock. 



The date of completion of wing primary molt was significantly earlier and the 

 duration of wing molt was shorter in exhibition stock than in production stock. 

 The number of eggs laid by production stock during wing molt was much greater 

 than the number laid by exhibition stock. The date of onset of wing molt was 

 more important and the mean length of the biological laying year was character- 

 istically greater in the stock bred for high fecundity. 



PART II. 

 MOLTING BEHAVIOR IN PRODUCTION-BRED RHODE ISLAND REDS 



Data on Rhode Island Reds bred for high fecundity over a seven-year period 

 are presented for both males and females. During the first three years preliminary 

 records were collected. In the spring of 1941 specific matings were begun in an 

 attempt to establish two lines, using only birds bred for high fecundity. Line A 

 was started with females laying for a very short period after wing molt began, 

 mated to a male that completed his wing molt early. Line B was begun with 

 females showing the ability to lay for a long time after wing molt started, mated 

 to a male that completed his wing molt late. Three generations were produced 

 in the two lines. 



Attention will be given first to all production-bred stock, using the same meas- 

 ures as were applied in Part I. 



Males 



TIME REQUIRED FOR MOLTING 



Observations extended over a six-year period and include a total of 44 males 

 bred for high fecundity. Consideration is given to the time interval between the 

 start and completion of molt in six feather regions. The average date of comple- 

 tioii is also recorded. 



The number of days required to complete the molt did not differ greatly in 

 most of the feather tracts. In the lower leg area, the time required was very short. 

 Wing primaries were molted slowly, requiring on the average about 101 days. 

 Males finished the molt in the neck and back regions first; the breast was com- 

 pleted soon after; the thigh and lower leg were molted somewhat later; and all 

 males had shed all wing primary feathers by October 30. 



