.as r . >. MASSACHUSETTS 



AGRICULTURAL EXPERIMENT STATION 



BULLETIN No. 298 JUNE, 193.^ 



The Significance of 



Length of Biological Laying Year 



in Production Breeding 



By F. A. Hays and Ruby Sanborn 



High persistency has long been recognized as an important factor in 

 breeding for egg production. In previous studies, however, persistency 

 has been considered only within the limits of the 365-day pullet laying 

 year. The studies here reported were undertaken to discover whether 

 birds that continue to lay without interruption for 13, 14, or 15 months 

 are superior for breeding purposes to birds laying for 9 to 12 months 

 before molting. 



INLA.SSACHU SETTS STATE COLLEGE 

 AMHERST, MASS. 



