54 POULTRY PRODUCTION 



that whereas the wild ^lalhird duck in a state of nature 

 lays only twelve to eighteen eggs in the year, it will lay from 

 eighty to one hundred if they are removed as fast as laid 

 and the bird kept confined in a pen at night. Hauke, 

 by regularly removing the eggs, got forty-eight in succession 

 from a common wryneck. Wenzel in the same way brought 

 a house sparrow's productivity up to fifty-one eggs." 



It is i)robable, however, that the practice of frequent 

 gathering has long since reached its limit of effectiveness and 

 that further improvement will be reached througli breeding, 

 supplemented I)y proper housing and feeding. 



Increased fecundity seems to ha\e caused longer periods of 

 time to elai)se between seasons of broodiness. In general, 

 it may be said that the broodiness of a breed is in inverse 

 proportion to its fecundity. With the ^Mediterranean breeds 

 this is true to such an extent that tlie I^eghorns are freciuently 

 termed a non-setting breed. 



The increasingly general use of the incubator is having 

 the result of further discouraging the exercise of the maternal 

 instinct. Where incubators are employed, the effort is likely 

 to be to " break up" the broody hen with the hope that less 

 time will be lost from laying. 



The vitality of the race has been lowered largely through 

 combined poor selection and inbreeding. With the breeds, 

 the practice has been to choose as breeders those liirds which 

 show the breed type or color characteristics to the greatest 

 degree even though they are not physically fit. Combined 

 with this has been the effect of inbreeding these individuals 

 to fix their characteristics and the promiscuous inl)reeding 

 that often accompanies the mongrel flock. 



Classes, Breeds, and Varieties. — The breed is the basis of 

 the classification of poultry. It may be defined as a group of 

 domestic birds closely approaching a certain specific shape. 

 The breed name is the one identifying any well defined and 

 recognized type, such as Plymouth Rock, Wyandotte, 

 Leghorn, Brahma, or Iiunner, and the birds conforming 

 closely to those types are said to be members of those respec- 

 tive breeds. 



The breeds are for convenience both subdivided and 



