3 LL550NS IN POULTRY KLLPING - SLCOND SE.RIL5. 



uniformly of an intermediate type, or that desired qualities are always reproduced. In opera- 

 tion the law " like produces like," is modified, as we shall see, by the fact that it includes the 

 more remote as well as the immediate parents, but, as we shall also see, these modifications of 

 and seeming variations from the law are strictly in accordance with it, and afford no basis 

 whatever for assuming that the law fails to operate in regard to any characteristics or qualities. 



That it often happens that fowls in which some superficial qualities have been improved or 

 Intensified by inbreeding have at the same time deteriorated in size, stamina, and productive- 

 ness, no one familiar with the phenomena of breeding poultry would deny. But as has 

 already been pointed out it also often happens that size, stamina, and productiveness are 

 diminished in fowls that are not inbred. In such cases the explanation given and it i the 

 correct explanation is that lack of size, stamina, and productiveness are due to breeding 

 from birds lucking in these points. They may also be due to external causes, but these need 

 not be considered here. 



Now if in mating unrelated fowls it is necessary to select for size, stamina, and productive- 

 ness, if we wish to reproduce those qualities in the offspring, it is also necessary to use the 

 unie care in selecting for matings of related fowls. And if by selecting for a mating of 

 unrelated fowls, specimens having the size, stamina, and productiveness we want in their 

 offspring, we, as a rule, get those qualities in the offspring; then if we select in the same way 

 for a mating of related fowls, we may reasonably expect to get offspring like their parents in 

 these essential qualities. We not only may reasonably expect to get them, but we do get them 

 as regularly as we get results in any other kind or class of qualities. And the reason many who 

 inbreed for fancy points, and some who make experiments in inbreeding, note a loss of " prac- 

 tical" qualities is that they failed, in making their matings, to provide for the retention of those 

 qualities. 



To cite the available evidence in support of the propositions I have just laid down would 

 extend this lesson beyond reasonable limits, but I^an assure the reader that every statement I 

 have made can be amply supported, and also that if he needs or wants first hand proof he can 

 readily obtain it by testing the matter for himself, observing that a proper test requires that the 

 immediate parents be not deficient in any quality it is desired to have conspicuous in the 

 progeny. 



Why Inbreed? 



So far I have been trying to show that inbreeding is not necessarily a cause of deterioration 

 in practical or in any otner qualities, and so to convince the reader that inbreeding is a legiti- 

 mate and useful means in breeding poultry. Now I want to take the reader one step further 

 and show him that inbreeding is not merely a method to be considered equally with the practice 

 of constantly or periodically introducing new blood, but that it is a better method in fact, the 

 only method by which high excellence and uniformity can be reached and maintained. 



Reference has been made to the fact that the operation of the law " like produces like," is not 

 Simited to the qualities of the immediate parents, but include also those of more remote ances- 

 tors. 



According to a law, known as Dalton's law of heredity, based upon observed facts of 

 heredity, the general rule is that an individual inherits : 



One-fourth of his qualities from each parent. 



One-sixteenth from each grandparent. 



One sixty-fourth from each great-grandparent. 



One two hundred and fifty-sixth from each great-great-grandparent. 



An individual has two parents, four grandparents, eight great-grandparents, sixteen great- 

 great-grandparents. Then 



From 2 ancestors in the first preceding generation he inherits one-half of his qualities and 

 <}h:iracteristics. 



From 4 ancestors in the second preceding generation he inherits one-fourth. 



From 8 ancestors in the third preceding generation he inherits one-eighth. 



From 16 ancestors in the fourth preceding generation he inherits one-sixteenth. 



From 30 ancestors in the four preceding generations he inherits fifteen-sixteenths of his char- 

 acteristics and qualities, leaving but one-sixteenth of his inheritance to come from the progres- 



