FUNDAMENTAL PRINCIPLES 225 
Fundamental Principles.—As a science, breeding is both com- 
plex and varied. This is in part due to the obscurity surrounding 
many of the phenomena, and to the great degree of variation in 
results obtained under apparently the same conditions, also in part 
to the influence which the purity of the individual exerts, as shown 
in the results of future transmission. 
Fortunately, however, the fundamental principles of the science 
of breeding, the complete understanding of which is essential to 
success in practical breeding, are few in number, and readily under- 
stood. These principles are as follows: 
1. Decide upon a standard of excellence, which may be either 
real or imaginary, and always breed toward it. 
2. Always breed from parents both of whom conform as closely 
as possible to this standard. 
3. Always breed from parents which are as purely bred as it 
is possible to obtain them,—that is, birds which have long been 
bred without the addition of alien blood. 
4. Study the individuals, and endeavor to mate them so that 
the faults of the parents will be corrected in the offspring. 
5. Practise a rigorous selection from hatching time to maturity, 
and especially when mating the breeding hens. 
6. Always consider environment, such as housing and feeding 
conditions. 
Breeding toward a standard of excellence gives the breeder a 
guide by means of which he can frequently estimate his progress. 
By following this guide without deviation definite results may be 
much more quickly attained. The standard may be written or it 
may be carried in the mind of the one engaged in breeding. In 
the former case, one prepared by an association is generally used. 
At the present time the American Poultry Association publishes 
the “‘ American Standard of Perfection,” in which are given the 
requirements of-all standard-bred poultry. In the absence of this 
standard the high excellence and uniformity now attained, as seen 
at.the large poultry shows, would be impossible. 
The necessity of breeding only from parents which conform as 
nearly as possible to the standard is based on the law of heredity 
that like produces like, and that, in order to secure a given progeny, 
the more nearly the parents conform to the standard the greater 
are the chances that the offspring will develop the desired qualities. 
The study of the science of breeding has shown that with an 
increased admixture of alien or foreign blood there is always a pro- 
15 
