APPLICATION OF PRINCIPLES OF BREEDING 485 



to variation in the individuals nearest the type. A skilled breeder 

 never uses, in his regular matings of an established variety, birds 

 varying conspicuously from the type which produces the standard 

 type. Experience shows that, when the object is to produce uni- 

 formity of type and high average merit, the most reliable breeders 

 are those individuals with the fewest faults. The " good all-round 

 bird " is almost invariably more valuable as a breeder than the 

 bird conspicuous for special excellence of one character or a few 

 characters. 



Inbreeding and line breeding. Inbreeding refers to matings of 

 individuals that are near akin. Line breeding is applied to various 

 plans designed to conserve blood and race character without in- 

 breeding. Theoretically, plans of breeding may be, and have been, 

 worked out which would give the breeder, for use at frequent inter- 

 vals, individuals bred in the same way from the same origin, — the 

 same blood separated by several generations. Possibly the specifi- 

 cations could be carried out in practice, but the work is too com- 

 plicated and the results are too uncertain, and experience in close 

 breeding soon shows the breeder that it is not necessary to resort 

 to such methods to avoid inbreeding. 



The most common form of line breeding is to maintain a male 

 line intact, though occasional or even regular changes are made in 

 the female line. Such line breeding gives better results than when 

 breeding lines are crossed and recrossed irregularly: If the head 

 of the line was an exceptional bird, and his male descendants used 

 for breeding in each generation resemble him very closely, the 

 type cannot fail to be strongly impressed on the stock, though 

 females of somewhat different breeding are occasionally used. In 

 most cases, when results of line breeding are conspicuously and 

 regularly good, the breeder practices close breeding to a much 

 greater extent than he thinks it wise to admit to a public with a 

 prejudice against it. 



Close breeding. The term '" close breeding " describes the prac- 

 tice of the best poultry breeders more comprehensively than the 

 more familiar terms " line breeding " and " inbreeding." Close 

 breeding is necessary to secure such likeness in parents that 

 similar uniformity may be produced in their offspring. Since an 

 individual inherits, on the average, only one half of its characters 



