CHARACTERISTICS OF NON-BROODY AND INTENSE 

 BROODY LINES OF RHODE ISLAND REDS 



By F. A. Hays, Research Professor of Poultry Husbandry 



INTRODUCTION 



American breeds ol poultry such as the I'lyniouth Rock, Rhode Island Red 

 and Wyandotte normally exhibit a considerable degree of broodiness. Within 

 recent years, however, the development of flocks for high fecundity has greatly 

 reduced the amount of broodiness in these birds so that some flocks compare very 

 favorably with Leghorns in freedom from broodiness. For example, the Massa- 

 chusetts Agricultural Experiment Station flock of Rhode Island Reds has been 

 reduced from 90 per cent broody in 1913 to about 14 per cent broody in the pullet 

 year at the present time. A similar change has taken place in many flocks of the 

 American breeds throughout the world. 



The lowering of egg production by loss of time during broody periods is widely 

 recognized. Goodale, Sanborn and White (1920) showed very definitely that 

 Rhode Island Red females lose from 11 to 66 days in non-productive broody 

 periods during the pullet laying year. Hays and Sanborn (1927) pointefl out a 

 net correlation of .5630+ .0097 between total days broody and annual production 

 during the pullet year. Jull (1932, p. 228) states that 494 Rhode Island Reds at 

 the U.S. Animal Husbandry Experiment Farm that were non-broody in the pullet 

 year averaged 204.78 eggs compared with 477 that showed broodiness and aver- 

 aged 179.65 eggs. 



This report concerns itself with two lines of Rhode Island Reds bred for non- 

 broodiness and intense broodiness, respectively, for the nine-year period of 1923 

 to 1931. Care was taken to avoid close matings so that with few exceptions mat- 

 ings no closer than cousins were made. It was necessary to introduce males and 

 females occasionally from the production-bred flock in order to avoid close matings. 

 Mating pens in the two lines were generally made up in part of tested hens and 

 cocks and in part of untested pullets and cockerels. Breeding stock was selected 

 in both lines for similarity in all traits affecting fecundity, except broodiness. 

 The non-broody line was selected constantly for freedom from broodiness and 

 the broody line for intense broodiness. All female breeders in the non-broody line 

 were free of broodiness in their pullet year and all dams in the broody line ex- 

 hibited broofliness the first year. 



EXPERIMENTAL RESULTS 



The most important inherited characters affecting egg production are age at 

 sexual maturity, winter pause, intensity, broodiness and persistency. These five, 

 according to Hays and Sanborn (1927, loc. cit.), are responsible for about 75 per 

 cent of the variation in annual production in Rhode Island Reds. 



1. Age at First Egg 



Data on 1207 broody Rhode Island Red pullets hatched from 1916 to 1925 at 

 this Station show that the regression of total days broody during the first laying 

 year on age at first egg was not strictly linear. The correlation ratio was found to 

 be .1552. +^0189 and positive in nature. The magnitude of this constant is too 

 small to indicate any significant association between age at sexual maturity antl 

 total days broody. 



Table 1 gives the percentage of broody daughters in the two lines each year 

 together with the means for the experimental period. 



In general the non-broody line showed a greater absolute decrease in mean age 



