ANNUAL REPORT, 1931 239 



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

 Ruby Sanborn). Complete data on the cost of raising pedigree pullets and cock- 

 erels to 162 days of age were collected on the Station flock and reported in 

 Poultry Science, May, 1931. All data on time required to reach standard egg 

 weight have been tabulated for use. Data on types of intensity and on persist- 

 ency have been prepared for publication. 



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

 for standard qualifications above gave an average annual production of 130 eggs. 

 Those selected for color from the production strain averaged 196 eggs. First- 

 generation females produced by crossing high-fecundity females with a standard- 

 bred male exhibited early sexual maturity, high intensity, and high persistency, 

 further substantiating the dominance of these traits. Broodiness was increased 

 to 55 per cent. The mean annual egg record of this first generation was about 195. 



In plumage color the first generation cross is intermediate between the parent 

 color. There is, however, a considerable range in plumage color. The effects of 

 heterosis were shown by increased body weight. 



Determination of Genetic Laws Governing Results of Inbreeding. 



(F. A. Hays). Mating father on daughters resulted in a marked decrease in 

 annual production as compared with the parental stock. The mean egg record 

 of the inbreds was 180 eggs while that of the parental stock was well above 

 200 eggs. The second generation produced by half brother-sister matings is not 

 promising. 



Hereditary and Environmental Characteristics Affecting Variability 

 in Egg Production. (F. A. Hays). This experiment has been concluded with 

 the generation hatched in 1930. Results will be published in the near future. 



Factors Affecting Egg Weight and Shell Character in Domestic Fowl. 



(F. A. Hays). Three lines are being developed based on the ability of the females 

 to lay 52-gram, 57-gram and 59-gram eggs, respectively, in the month of Decem- 

 ber. The fourth generation was hatched in 1931. The data so far substantiate 

 the proposed theory that gene A for small eggs is epistatic to gene B for large eggs. 



Relation of Intensity or Rate of Laying to Feather Pigmentation. 



(F. A. Hays). This project terminates with the generation hatched in 1930. 

 Data are being prepared for publication. 



DEPARTMENT OF VETERINARY SCIENCE 

 J. B. Lentz in Charge 



Poultry Disease Elimination Law. (H. Van Roekel, K. L. Bullis, O. S. 

 Flint, and Miriam K. Clarke). During the 1930-31 season, 402,983 blood samples, 

 representing 356,810 chickens in 447 flocks, were tested for pullorum disease. 

 Compared with the previous season, increases were observed in the number of 

 tests and the number of tested birds. The average percentage of infection was 

 1.47, the lowest attained in eleven seasons. The number of birds in 100 per cent 

 tested, non-reacting flocks increased. Infection was found in 26 flocks which 

 were non-reacting in 1929-30. The reported possible sources of infection were 

 failures to observe sound eradication measures. No reactors were detected among 

 2,099 fowl other than chickens. 



