74 MASS. EXPERIMENT STATION BULLETIN 327 



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

 Ruby Sanborn.) Data have been prepared and published on "Crossing 

 Production and Exhibition Rhode Island Reds," Bulletin 316. The following 

 papers are now in press: "Studies on the Inheritance of Persistency," "Numbers 

 and Uniformity in Experimental Lots," "The Inheritance of Sexual Maturity 

 in Rhode Island Reds," and "The Time Interval Between Eggs in Rhode 

 Island Reds." 



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

 behavior of plumage color in two lines of exhibition Rhode Island Reds is being 

 studied. One line is being selected for plumage color alone and the other line 

 is being bred for known fecundity characters. Some very satisfactory egg 

 records have been made by the second line. 



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

 records on feather development in the different feather tracts from hatching 

 up to nine weeks of age are available on about 1800 chicks. Records on back 

 feathering at eight weeks of age are available on over 6000 chicks. These data 

 indicate that both a sex-linked and one or more autosomal genes are concerned 

 in rate of feathering of Rhode Island Reds. 



Breeding for Low Mortality. (F. A. Hays.) High and low mortality 

 lines are now in the second generation. The data are inadequate at present, 

 but they suggest that hereditary factors are of considerable significance in 

 relation to mortality rate in the laying house. 



Breeding for High and Low Resistance to Fowl Paralysis. (F. A. 



Hays, C. S. Gibbs, W. C. Sanctuary, and J. H. Vondell.) The incidence of 

 paralysis in the first generation was as follows: Line A, -23 percent; Line B, 26 

 percent; and Line C, 10 percent. In the second generation the incidence of 

 paralysis fell to 11, 9 and 5 percent, respectively, in the three lines. A pre- 

 liminary study of the data suggests that paralysis may occur in birds lacking 

 one dominant gene for resistance, but that a dominant inhibitor may prevent 

 its occurrence in such individuals. 



DEPARTMENT OF VETERINARY SCIENCE 

 J. B. Lentz in Charge 



Poultry Disease Control Service. (H. Van Roekel, K. L. Bullis, O. S. 

 Flint, and M. K.Clarke.) 



1. Pullorum Disease Eradication. The 1934-35 testing season has revealed 

 a marked increase in the volume of testing along with progress in reducing the 

 amount of infection among the tested flocks. A total of 247 flocks (including 

 three flocks other than chickens) was tested. The number of blood samples 

 tested from the 244 chicken flocks was 301,887, of which only 0.39 percent were 

 positive. This percentage is the lowest attained during the fifteen-year testing 

 period. Progress in eradication is further noted in that the percentage of flock 

 ovners who tested all the birds on the premises has increased from 66.8 in 

 1933-34 to 74.5 in 1934-35. Among the 213 non-reacting flocks, 163 were 100 

 percent tested. The number of flocks which were tested lor three or more 

 consecutive years was 161, of which 149 were non-reacting. The average per- 

 centage of positive tests for this group was 0.18, the lowest attained durinp the 

 testing history in the State. It is clearly evident that the practice of annual 



