no MAINE AGRICULTURAL EXPERIMENT STATION. I913. 



poultryman who does not keep individual pedigrees, and could 

 scarcely afford to do so if he wanted to, the safest and wisest 

 plan to follow in breeding is to make matings without any 

 thought whatever of the relation to one another of the indi- 

 viduals mated. In some instances they will be closely related, 

 in others not so, purely as a result of chance. If only indi- 

 viduals of high constitutional vigor are used as breeders no 

 thought need be taken as to relationship, and there will be no 

 necessity of going out of the flock to get "new blood" to reju- 

 venate the stock. Further if "new blood" is not brought in 

 there will be sufficient inbreeding purely from chance to bring 

 about in time (in a flock of not too diverse origin ) a consider- 

 able degree of purification in respect to selected characters. 



Introduction of new blood for purposes of rejuvenation or 

 reinvigoration, which is one of the commonest practices of the 

 poultryman, is, as ordinarily done, one of the surest Avays to pre- 

 vent any real or permanent improvement of his stock by breed- 

 ing. The difficulty here is that when one introduces new blood 

 he runs the risk of introducing a whole set of characters infe- 

 rior in their degree of perfection to what he already has in his 

 own stock. The real cause which so frequently leads poultry- 

 men who should know better to take this risk is a failure rigor- 

 ously to select breeding birds for high constitutional vigor. 

 The average poultryman finds it very hard to discard some 

 particularly fine specimen just because it shows a little weak- 

 ness in one way or another. He is disposed "just this once" to 

 let the bird by, and use it as a breeder. This practice continued 

 will make "new blood" necessary for rejuvenating purposes. 



Again the careful breeder often finds himself in this situa- 

 tion. He has by well planned and executed breeding brought 

 his stock up to a particular level of excellence. There the 

 improvement stops. His birds breed true to that particular 

 degree of cjuality but cannot be made to attain a higher degree. 

 In other words, he has substantially purified his stock relative 

 to the characters which interest him. But he sees that the stock 

 of some other breeder is measurably better than his. If A is to 

 get his stock up to the R level he must introduce some B blood. 

 This has long been the poultryman's procedure, and if done in 

 the right Avay, it is found to be as successful in practice, as it is 

 justifiable in theorv in the light of modern ideas respecting 



