86 THE BIRDS 



Laws of Breeding. — Before discussing special methods of 

 mating and breeding for definite purpose, the common laws 

 of breeding will be briefly stated, for these must be under- 

 stood before one can mate fowls intelligently. 



The most common and one of the most stringent rules in 

 the reproduction of animals is the law of heredity. In plain 

 words, this means that like produces like, and that the 

 young will, in large measure, show the same characteristics 

 as the parents. The action of this law makes it essential 

 for us to mate and to breed from birds which possess those 

 characteristics we desire in the progeny. Scientists have 

 demonstrated that this law is fixed and absolute. Further- 

 more it has been found that the results of this law of heredity 

 can be computed definitely in figures. The discovery of these 

 facts and their application to poultry breeding are of the 

 greatest value to the poultryman, because they enable him to 

 mate his birds intelligently for the purpose he has in view. 



The second important law of breeding is that called vari- 

 ation, and this law is antagonistic or in opposition to the 

 law of heredity. Stated in simple words, it means that 

 many of the characteristics shown by the progeny will differ 

 from those possessed by the parent. This is what is known 

 in science as a coxmteracting force. Just as we have laws 

 of heredity and variation working in opposition to each 

 other, so we have the laws of gravity and centrifugal force 

 working against each other to hold the earth in balance. 

 Observation of the workings of this law of variation teaches 

 us that there are different kinds of variation. There may 

 be variation in color and quality, in structure and size, in 

 egg production, and in flesh forming ability. It is because 

 of this law of variation that the poultryman is able continu- 

 ally to improve his flocks. By studying these variable 

 characteristics, and by constantly selecting and breeding 

 the varieties best suited to his needs, he will secure better 

 and better birds. 



