ANNUAL REPORT, 1941 95 



DEPARTMENT OF POULTRY HUSBANDRY 

 R. T. Parkhursl in Charge 



Broodiness in Poultry. (F. A. Hays.) A number of specific facts have been 

 established in this study of the inheritance of the broody instinct in Rhode Island 

 Reds. Some of the most significant findings are the following. The length of 

 the non-productive period associated with broody behavior remains rather con- 

 stant at about fifteen days. Degree of broodiness as measured by the number 

 of broody periods is governed by inheritance. The time of appearance of the 

 broody instinct in the life of a female is highly variable. In flocks bred to eliminate 

 the broody instinct, the onset of broody behavior in individual females has been 

 about 57 percent in the first laying year, 34 percent not until the second laying 

 year, and about 8 percent not until the third laying year. These three classes 

 of females when used as breeders gave about the same percentages of broody 

 daughters. The selection of female breeders that did not exhibit the broody trait 

 during their first two laying years was effective in reducing the incidence of brood- 

 iness in the flock. There is no evidence of sex-linked inheritance. 



At present efforts are directed toward the establishment of an entirely non- 

 broody line by applying all of the information now in hand. 



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

 Sanborn.) This project is devoted entirely to the preparation and analysis of 

 experimental data used for publication. During the year the following papers 

 have been prepared: The Importance of Length of Incubation Period in Rhode 

 Island Reds, Bulletin 384; Breeding for High Viability, a study covering seven 

 years, has not yet been published; A Preliminary Study of Molting Behavior, 

 covering three years, has not yet been published; and A Study of Variation in 

 Egg Weight, covering five years, is now in preparation. 



A Genetic Study of Rhode Island Red Cobr. (F. A. Hays.) This study has to 

 do with the genetic complex concerned in the inheritance of Rhode Island Red 

 plumage and possible relationships between characters affecting fecundity and 

 plumage color. Two lines of birds are being carried, one breeding true for late 

 sexual maturity and the other selectively bred for early sexual maturity. There 

 is some evidence that one or both of the dominant genes for early sexual maturity 

 afi"ects plumage color. The relation between the red of the Rhode Island Red 

 plumage and the buff of the Orpington is also being studied. 



Rate of Feathering in Rhode Island Reds. (F. A. Hays.) This experiment is 

 concerned primarily with the genetic aspects of rapid and slow chick feathering. 

 To study this problem three lines have been developed with respect to rate of 

 chick feathering; namely, a rapid-feathering line produced exclusively by the 

 use of breeding males that showed complete back feathering at eight weeks of 

 age; a slow-feathering line bred entirely from sires showing the absence of back 

 feathering at eight weeks of age; and a check line bred primarily for high fecundity, 

 with some of the sires rapid feathering and some slow feathering. 



In the spring of 1941 the seventh generation was produced in the three lines, 

 and gave the following percentages of rapid-feathering sons at eight weeks: 

 line 1, 100; line 2, 10; and the check line, 84. The chicks were also classified 

 for the sex-linked gene for rapid feathering at twelve days of age. The males in 

 the three lines gave the following percentages with the sex-linked rapid-feathering 

 gene: line 1, 49; line 2, 0; and the check line, 6. An attempt was also made to 

 separate the rapid- and slow-feathered females by grading the feather growth in 

 the back region at four weeks of age. 



All data available indicate that in Rhode Island Reds the sex-linked gene for 



