494 



POULTRY CULTURE 



as breeders the greatest producers are inferior to average good producers. Hens 

 producing two hundred eggs in a year are not as likely to produce daughters 

 that are extraordinary layers as are hens that have performed more moderately. 

 The great laying individuals come generally from moderate layers of strong 

 constitution. Extreme heavy laying saps vitality and tends to sterility. 



In the light of the commonly observed facts as to the increase of individual 

 egg production, the extraordinary layer appears as the culmination of the devel- 

 opment of the tendency and capacity to develop eggs. In general, what may be 



FIG. 483. Silver-Gray Dorking cock, ideal table shape. (Photograph from 

 owner, Arthur C. Major, Ditton, Langley, Bucks, England) 



regarded as the supreme effort in egg production leaves the individual without 

 reserve force for reproduction. A rare individual with vitality enough for both 

 may prove a good producer of heavy-laying stock. Such an individual, of great 

 prepotency, might be bred, with striking results in high egg production, for a gen- 

 eration or two, but the steady drain of egg production, and its ordinary effect on 

 reproduction, tends always to abrupt cessations of progress in this direction. 



Influence of the male on production of eggs. If the supply of elementary 

 eggs is always ample the only influence of the male to be considered is his 

 influence on those characters which affect the capacity to develop eggs. It has 



