86 POULTRY BREEDING AND MANAGEMENT 



mating less than a dozen took after the pure-bred male in 

 color; the balance were all white. The practical point 

 brought out in this experiment is that prepotency does not 

 follow blood lines, and that in mating a cross-bred or mon- 

 grel to a pure-bred it does not necessarily follow that the off- 

 spring will take after the pure-bred in all characters. Pre- 

 potency is not always measured by length of pedigree 



While Mendelism is yet in an " embryonic " stage, and 

 while confusion prevails as to its teachings in certain re- 

 spects, a clue has undoubtedly been found that will lead 

 the way to important developments in the future. 



Outcrossing. The term outcrossing is frequently used 

 by breeders. It means the use of males from strains dif- 

 ferent from those of the females, but belonging to the same 

 breed or variety. It is breeding within breed lines, but not 

 within family lines. If a careful system of outcrossing be 

 practiced, resort to crossing will probably seldom be neces- 

 sary to keep up the stamina of the breed. This is the main 

 purpose of outcrossing. Another object in outcrossing is 

 to improve the family or strain in some point or character 

 which it may lack by introducing blood from another strain 

 which is strong in the character the other lacks, 



Inbreeding. The mating together or breeding together 

 of closely related males and females, is inbreeding. Where 

 the relationship is close, inbreeding is the term used, but 

 where the relationship is more or less remote it is called by 

 many authorities line breeding. The only difference, if 

 there should in reality be any difference, between inbreed- 

 ing and line breeding, is a difference in degree of relation- 

 ship. It is doubtful whether it would not be just as well 

 to call it all by the one name, "inbreeding." 



Breeding of brother and sister together is the closest 

 kind of inbreeding. Mating parent to offspring is also 

 close breeding, though this is frequently called line breed- 



