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POULTRY CULTURE 



layers may be very small. Special points in selecting layers will be 

 treated in connection with the selection of breeding stock to pro- 

 duce layers. Systems for selecting layers, based usually on phys- 

 ical measurements, are unreliable. The trap nest and individual 

 record are necessary to select the individual producers with cer- 

 tainty, but such methods are too expensive to be profitably used 

 with laying stock. Judicious selection on general appearance will 

 eliminate most of the poor producers. It is usually cheaper to 

 feed any that this method overlooks than to go to the expense of 

 identifying them. 



Effect of age on production. Age and egg production are not 

 directly correlated, though they often seem to be. General com- 

 parisons of records of pullets with older hens, and of records of the 

 same flock of birds through several years, indicate production at its 

 highest during the first year, and so rapidly diminishing that only a 

 small proportion of hens continue profitable layers after the second 

 year (for the heavier breeds) or third year (for the lighter breeds). 

 Instances of flocks, as well as individuals, furnishing exceptions to 

 the general condition are, however, numerous enough to show that 

 production depends primarily upon constitution and condition, and 

 upon age only as age affects condition through the cumulative 

 effects of unfavorable influences and the natural diminution of 

 vitality. As a rule, only about half the pullets selected for layers 

 at maturity will pass as rigid a test of condition a year later, and 

 not more than one fourth of a third of those reserved for a second 

 winter will pass a third examination. At three years of age, and 

 even older, hens in good condition may be more valuable for egg 

 production than the poorer pullets. 



