158 Farm Poultry 



produce individuals of superior merit, he will 

 naturally try to perpetuate this superiority and to 

 reap the advantages of it through successive gene- 

 rations in his herd or flock. This has been made 

 possible through in-and-in-breeding. Almost with- 

 out exception marked improvement is first noted 

 in one or two animals. If the progeny of these 

 animals are bred to each other or to one of their 

 parents, the young resulting from this mating will 

 contain a much larger percentage of the "blood" 

 of the animal in which the improvement was noted 

 than could be obtained in any other way. Con- 

 sequently the chances that the improvement will 

 be transmitted are considerably enhanced. 



In other words, in-and-in-breeding enables the 

 breeder to accumulate or "pile up" the blood of 

 a superior animal in the descendants of this valu- 

 able individual. To make use of an illustration, 

 it may be supposed that A and B represent two 

 animals of the same breed and that A is of superior 

 merit. If these animals are mated, the blood of 

 the progeny will be represented by one-half A and 

 one-half B. If A be bred to one of the progeny, the 

 blood of the offspring of the last union will be repre- 

 sented by three-fourths A and one-fourth B. This 

 practice may be repeated in succeeding generations 

 and would be accepted by all as in-and-in-breeding. 

 As the percentage of blood is increased the improve- 

 ment is more likely to be perpetuated. 



