90 MASS. EXPERIMENT STATION BULLETIN 369 



Rate of Feathering in Rhode Island Reds. (F. A. Hays.) Eaily feathering 

 in Rhode Island Reds may be measured by the development of complete back 

 feathering in males at eight weeks of age. Females in this breed are for the most 

 part well feathered over the back at eight weeks or younger. 



Two lines are being developed from the standpoint of dorsal feather growth, 

 and are now in the sixth generation. One line is selectively bred by using sires 

 that have shown complete back feathering; the other has been developed by using 

 sires that have lacked back feathering at eight weeks of age. 



A total of 155 cockerels was produced from two sires in the early-feathered line. 

 The first sire gave 69 percent early-feathered sons, and 18 percent of his sons 

 showed tail development at 12 days of age; 12 percent of his daughters had tail 

 development at 12 days. The second sire in this line gave 63 percent early-feath- 

 ered sons and 26 percent of his sons showed tail development at 12 days; 51 

 percent of his daughters had tail development at 12 days. The 155 males in the 

 early-feathered line gave 65 percent early feathered, and about 24 percent had 

 tail deve opment at 12 days. The development of back feathering was not 

 closely related to the development of tail growth at 12 days, the latter apparently 

 being due to the sex-linked gene reported by Warren in Leghorns. In the early 

 line there were four families in which all males had complete back feathering. 



The late line consisted of 36 males and 32 females from five different families, 

 all sired by one late-feathered male. These males showed 100 percent late feath- 

 ering at 12 days and at 8 weeks of age. The females also showed 100 percent late 

 feathering at 12 day::. 



The data so far collected seem to mdicate that early feathering in the dorsal 

 region in males is due to several recessive autosomal genes and that a sex-linked 

 recessive need not be present to produce the desired phenotype. Barred Plymouth 

 Rock chicks in the Station flock show a high degree of back feathering but not 

 a single individual has shown tail development at 12 days. 



The Effectiveness of Selective Breeding to Reduce Mortality in Rhode Island 



Reds. (F. A. Hays.) Cooperative project with Regional Poultry Research Lab- 

 oratory, East Lansing, Michigan. Two lines are being developed by selective 

 breeding: one selected for low mortality in the laying houses and the other for 

 high mortality in the laying houses. Selection of breeding stock to reproduce 

 these two lines is based entirely upon mortality rates with no consideration given 

 to fecundity characters or to egg characters. The fifth generation, hatched in 

 1938, has completed a full laying year. 



In the low mortality line 49 pullets were placed in the laying houses and 20 

 individuals died, giving a mortality rate of 40.82 percent. Eleven birds died from 

 cannibalism, six from undetermined causes and one each from ruptured yolks, 

 tumors, and prolapsus of the oviduct. The death rate was excessive because of 

 the high incidence of cannibalism. 



In the high mortality line 43 pullets were housed. The loss in the first laying 

 yeai was 25 birds, giving a mortality rate of 58.14 percent. Seven birds died from 

 cannibalism, 12 from undetermined causes, 3 from ruptured yolks, 1 from a cholera - 

 like disorder, and 1 from prolapsus of the oviduct. In this line there wa.s one 

 pullet that survived but never laid and another that laid but 36 eggs. 



The sixth generation was hatched in 1939. In the low mortality line 135 

 chicks were hatched, and the mortality to six months of age from all causes was 

 6.6 percent. In the high mortality line there were 153 chicks, with a mortality 

 rate of 10.46 percent for the first six months. There was one case of neurolympho- 

 matosis. 



In the low mortality line 45 pullets were placed in the laying houses and 41 cock- 

 erels were retained. These represent complete families. To December 1, 1939, 



