86 MASS. EXPERIMENT STATION BULLETIN 339 



second male also produced five families of daughters, four of which exhibited 

 broodiness. The total number of daughters was 30, and 5 of this number be- 

 came broody in the first laying year. In the entire flock bred for egg production 

 only 4.73 percent of the birds were broody during the first laying year. The 

 mode of attack appears to lie in the use of aged males and females that have 

 been shown by breeding tests to lack the dominant genes for broodiness. 



Breeding Poultry for Egg Production. (F. A. Hays and Ruby Sanborn.) 

 A number of phases of the problem of breeding for high fecundity have been 

 studied during the past year. The flock has been constantly selected for high 

 hatchability. The hatching records for 1936 show significant progress. From 

 eight pedigree hatches at weekly intervals during March and April, a total of 

 6,604 eggs set gave a mean hatchability of fertile eggs of 84.31 percent. 



Body weight has increased in the flock, the mean weight at first egg being 

 6.2 pounds for a mean age of 194 days. Egg size has been significantly increased 

 to a mean of 56.3 grams from first egg to January first. Broodiness stood at a 

 new low figure of 4.73 percent. Mean annual egg production for the flock just 

 finished was 220.4 eggs. This mean is based on all birds that survive, without 

 culling. Mortality rate of pullets in the laying houses was greatly reduced to 

 the low level of 13.2 percent for the first laying year. The production-bred 

 flock has also been improved in chick feathering. 



Statistical Study of Heredity in Rhode Island Reds. (F. A. Hays and 

 Ruby Sanborn.) Data have been prepared and published as follows: Studies 

 on the Inheritance of Persistency, Genetics 21:519-524, 1936; Winter Pause 

 in Rhode Island Reds, Station Bui. 329, 1936; Time Interval Between Eggs 

 of Rhode Island Red Pullets, Jour. Agr. Res. 52:633-638; Numbers and 

 Uniformity in Experimental Lots, Poult. Sci. 15:235-238, 1936; Inheritance of 

 Sexual Maturity in Rhode Island Reds, Proc. Sixth World's Poult. Cong. pp. 

 34-38, 1936; Hatchability as Related to Season and Hour of Laying (in press). 



A Genetic Study of Rhode Island Red Color. (F. A. Hays.) Two 

 lines of exhibition stock have been maintained. One line has been bred for 

 plumage color alone and the behavior of egg production character has been 

 studied. The other line has been bred for characters affecting egg production 

 without sacrificing desirable plumage color. Neither line has reached a high 

 production level but some promising families and individuals have appeared. 

 The difficulty in making progress in small units constantly appears. 



Rate of Feathering in Rhode Island Reds. (F. A. Hays.) Early- 

 feathered and late-feathered lines are being developed on the basis of back 

 feathering at eight to nine weeks of age. After three generations of breeding 

 the first line shows about 50 percent early feathered and the second line about 

 10 percent early feathered. The data point to two rather definite facts. First, 

 that early-feathered females cannot be distinguished from late-feathered females 

 at eight weeks of age. Second, that early feathering is recessive and depends 

 not only upon a sex-linked gene but also on two or more autosomal genes. 



Breeding for Low Mortality, (F. A. Hays.) Two generations of lines 

 bred for high and low mortality in the laying houses have complete records. 

 Each line has been selected entirely on mortality rate without regard to egg 

 production characters. Laying-house mortality in the first generation was 55 

 percent and 44 percent respectively for the two lines. The corresponding first- 

 year egg production for the survivors was 192 and 230. The second generation 

 hatched in 1935 gave a laying-house mortality of 19 percent and percent 



