4 MASS. EXPERIMENT STATION BULLETIN 429 



molting of the wing primaries was the most regular, as Marble (1930) had already 

 observed in Leghorns. 



Since the ability to lay while molting wing primary feathers varied widely, an 

 attempt was made in 1941 to establish two lines differing in this respect. Line A 

 was selectively bred for a short period of laying while molting; Line B was bred 

 for the ability to lay for a long period after the wing molt began; and both lines 

 were carried through three generations. All birds in lines A and B came from the 

 production-bred stock; all birds used in this experiment were pedigreed; and 

 all females were trapnested for the first laying year. 



Results are reported in two parts: I, a comparison of the molting behavior of 

 exhibition-bred and production-bred males and females; II, the records on pro- 

 duction-bred stock alone through seven generations. 



PART I. 



MOLTING BEHAVIOR IN EXHIBITION-BRED AND PRODUCTION-BRED 

 RHODE ISLAND REDS 



Males 



Molting behavior was studied in five exhibition-bred Rhode Island Red males 

 and twenty-five production-bred males hatched in 1938 and 1939. The observa- 

 tions began July 25 and were concluded on November 30, the usual period when 

 laying females go through their first annual molt at the end of the first year of 

 laying. 



Table 1.— Annual Molt in Males, 1939-1940. 

 Time required and date of completion. 



Feather Region 

 and Stock 



Number 

 of Birds 



Average 



Days 

 Required 



Date of 

 Completion 



Neck (Cervical) 



Exhibition 5 



Production 25 



Breast (Pectoral) 



Exhibition 5 



Production 25 



Thigh (Femoral) 



Exhibition... 5 



Production 25 



Lower Leg (Tibial) 



Exhibition 5 



Production 25 



Back (Dorsal) 



Exhibition 5 



Production 25 



Wing Primaries 



Exhibition 5 



Production 25 



