BROODINESS AND FECUNDITY IN FOWL Gl 



measured by tlie number of broody periods and by the mean length of broody 

 periods. Both Pearl (1914.) and Goodale (1920) have measured the length 

 of each broody period by the cessation of egg production associated therewith. 

 Goodale (loc. cit.), however, stresses the fact that winter pause and fall molt 

 may prolong tlie non-productive period for a considerable time interval beyond 

 the normal broody period. 



In the present studies, the observation has been made that tliere is a remark- 

 al)le degree of uniforniity in length of broody periods in the same individual. 

 In tiie occasional bird that goes broody during the fall or winter of her pullet 

 year, the winter pause may greatly lengthen the period of non-production. 

 In such cases we have allowed four days for the bird to begin laying after 

 removal from tlie broody coop to the laying house. Such birds are removed 

 from the broody coop only when they no longer siiow signs of broodiness. In 

 sucli cases any pause up to March first, of greater duration than four days 

 following removal of hen from broody coop to laying house, is not considered 

 a broody pause. 



Very frequently the laying J'ear terminates with a broody period and no 

 more eggs are laid for two or three months. In such cases the length of the 

 last broody period is calculated in the same manner as outlined above for the 

 winter season. This long period of non-production is without question due 

 largely to the onset of complete molt and not to broodiness. The fact that 

 non-broody birds exhibit this long period of non-production during molt is 

 very convincing evidence on the point in question. 



Relation of Bkoodiness to FECU^D1TV. 



In studying the relation of l)roodiness to fecundity, it has been necessary 

 to study the degree of correlation between broodiness and rate of laying, 

 times broody and mean length of broody periods, winter rate and annual 

 rate, winter rate and annual egg yield, annual rate and annual egg yield, and 

 broodiness and annual ea:g yield. 



Unpublished data at this Station indicate that rate of laying or intensity 

 is the most important single characteristic affecting egg yield. For tiiis rea- 

 son, tiie relation Itetween broodiness and rate is of extreme importance. 

 Either a positive or negative correlation between broodiness and rate would 

 be far more significant genetically than would the absolute correlation between 

 liroodiness and egg production; for egg production has already been shown by 

 Goodale and Sanborn (1922) to depend upon at least five characteristics and 

 one of these characteristics is rate. In the present study of tlie relation of 

 broodiness to fecundity these facts are fully considered. 



;. Correlation Between Times Broody and December Rate — Pullet Year. 



In this study pullets are included that were hatched on the following years: 

 1916, 1917, 1918, 1920, 1921, 1922 and 1923. The flock hatched in 1919 is not 

 included because no annual records are available for tluit year on account of 

 a disease epidemic. All Rhode Island Red pullets with normal records are 

 included. In addition to the major portion of each flock that was bred for 

 egg production, there are included a small number of inbred birds, a small 

 number bred for intense broodiness, a small number bred for color, and a 

 small number used in studying the inheritance of hatchability. Inasnuicii as 

 this report is a study of the relationship between broodiness and fecundity, 

 there is no conceivable reason why a rather heterogeneous flock should not 



