160 



POULTRY PRODUCTION 



be used to his limit after his real value is discovered. The 

 practice should be to use both males and females for breetling 

 purposes so long as they will produce a reasonable number 

 of vigorous chicks. There appears to be no good reason 

 why the average breeding life of both males and females 

 should not be at least fi\'e years. 



Longevity is of as great importance to the producer as 

 to the breeder. The profitable productive life of a hen is 

 generally considered to be limited to two years, 'i'his ncces- 



FiG. 7s 



S. C. \V. Letliorn, Kansas AS, nith a fiiurth-.viMr laying recmd of 22('i of;g» 

 Note button leg band whoso numlier can he seen for some distance. 

 (Courtesy of Kansas Agricultuial Experiment Station.) 



sitates the renewal of at least one-half the producing flock 

 each year,, an item of uncertainty with present methods and 

 one of great expense. 



As one step in develojiing a long-lived race of persistent 

 producers, no breeding females should be used which have 

 not lived at least two years and maintained the best of health. 

 This engages the aid t)f the great law t)f " the survi\-al of 

 the fittest" in the selection of the breeders. The producer 

 is then sure that his breeders at least have vitality enough 



