68 POULTRY BREEDING AND MANAQEMENT 



character. The practical lesson to the breeder is that he 

 should eliminate everything in the breeding and manage- 

 ment that may cause reversion when he is making satisfac- 

 tory progress. 



The Pure-Bred, or Purity in Breeding. We are accus- 

 tomed to considering pedigree as synonymous with purity 

 of breeding. The Shorthorn that can trace an unbroken 

 ancestry back to the Duchess family is a pure-bred. The 

 Berkshire that has a clear line of descent from Longfellow 

 an animal of superior excellence that belonged to a breeder 

 of Missouri about twenty years ago is a pure-bred Berk- 

 shire. If one of its ancestors had been crossed with a Poland 

 China a number of years ago, even though no trace of Poland 

 China could now be detected, and it would win in the show 

 ring, it would not be pure bred. The pedigree was every- 

 thing. But Mendelism has given a new meaning to pure 

 bred. It has shown us that purity of breeding has a physio- 

 logical basis. A bird or animal may be pure bred in respect 

 to one character and inpure in respect to another. A bird, 

 for example, may be pure in respect to the character 

 "comb," but not pure in respect to some other character. 

 If a cock and a hen of a single comb breed when mated 

 breed offspring with single combs, they are pure bred so far 

 as comb is concerned. 



If, however, some of the offspring are black and others 

 white they are not pure bred in respect to color of plumage. 

 They would be mongrels in color, but pure bred in comb. 

 It is a question of unit characters, not individuals. Again, 

 if a hen laying 150 eggs in a year, mated to a male from a 

 150-egg hen, produces offspring that lay less than 100 eggs, 

 she would not be pure bred in respect to egg production. 

 The parents are pure-bred when their own characteristics 

 are reproduced in the offspring with reasonable certainty. 

 A hen is a pure-bred egg producer if she transmits her egg- 



