6 MASS. EXPERIMENT STATION BULLETIN 316 



showed the same percentage of early-maturing birds; they were slightly superior 

 in intensity and non-pause, decidedly superior in winter egg weight, greatly 

 superior in mortality, and equal in egg production, but were low in hatchability 

 and in persistency. 



Class 8, representing the daughters of exhibition males mated to F2 females 

 was not equal to class 7 daughters in weight at sexual maturity, and there was a 

 much higher proportion of late-maturing birds. Class 8 contained no highly 

 intense and very few non-pause birds, and was inferior to class 7 in egg size, 

 hatchability, non-broodiness, high persistency, mortality rate, and egg produc- 

 tion. Compared with the checks, class 8 birds were inferior in all respects except 

 winter egg size and mortality rate. 



Class 9 includes daughters from various types of matings not already considered. 

 They were superior to the checks in body weight, sexual maturity, winter egg 

 weight, and mortality rate; they were inferior in hatchability, non-broodiness, 

 persistency, and annual egg production. 



In general, Table 2 indicates that hybridization increases body weight, especially 

 in the Fi generation; that early sexual maturity dominates late sexual maturity; 

 that high intensity depends on dominant genes; that winter pause is little affected 

 by crossing; that winter egg size is increased: that hatchability is improved only 

 in the first generation; that broodiness may be increased by hybridization; that 

 persistency is lowered by crossing; that laying-house mortality is reduced only 

 in the first generation cross; that annual egg production is above intermediate 

 between the two parent stocks in the first hybrid generation and tends to de- 

 crease in the F2 generation, but that production can be raised to a high level by 

 back crossing Fi and F2 females on production-bred males. 



PLUMAGE COLOR 1 



The general behavior of plumage color in the various crosses between the 

 characteristically light-colored production fowls and the essentially bay-colored 

 exhibition birds is of economic and scientific interest. Breeders often desire to 

 darken the shade of red because of market demands but definite information on 

 the behavior of color in inheritance is lacking. In Table 3 the surface color of 

 males and females is listed separately for the exhibition stock and for nine differ- 

 ent types of hybrid offspring. All records on plumage color were taken when the 

 birds were from five to six months of age. 



Surface Color 



Table 3 presents a summary of the adult surface color of male and female 

 hybrid offspring from ten different types of mating. 



'It i- a well-iknown fact thai in man) Rhode Island Red fowls the surface color and under color 

 vary in different body regions. There is, however, a rather intimate as tween shades 



of color in surface and feather fluff on the same bird in different body regions. For the sake of 

 simplicity in this study the plumage color has been consistently considered only in the mid-back 

 region which has been taken as representative of the plumage color in general. Thi.- method of 

 procedure would seem to be justified by the studies "f Warren and (lord 19 



