240 POULTRY BREEDING 
fowls the object is to improve on both parents. If Dar- 
win’s dictum were entirely true we should only need to 
mate high-class fowls together to produce high-class 
progeny, but unfortunately the Darwinian rule is weak- 
ened by the very large number of exceptions that occur 
when we try to work by it. There is a law which works 
to reproduce species, but when we come to work for indi- 
vidual specimens of high quality we find that the law of 
variation interferes and our best matings produce many 
inferior or very ordinary specimens, and the best the 
most skillful breeder can expect is to secure a few excel- 
lent birds, a somewhat larger number of good ones, a 
still larger number of standard birds and many culls, 
having defects that preclude their use in the breeding 
pens of a breeder who 1s careful about his bloodlines, for 
defects have a way of showing up in an intensified form 
in the progeny of any kind of stock. 
The poultry breeder must contend with several factors. 
He must be careful in making his matings, that he may 
secure both shape and color, and must at the same time 
breed from healthy stock only, for disease also intensifies 
itself when bred into young stock. A hen that has had a 
bad case of roup should never be used as a breeder, for 
the tendency to fall victim to the roup germ will be trans- 
mitted to her progeny, and there is reason to believe that 
such progeny will have less power of resistance to other 
diseases. So with any other diseases. Use for breeding 
only such fowls as have a perfect record for health, and 
especially those which, having good digestive power, are 
easy to keep. 
The poultryman who keeps standard poultry will of 
course have a copy of the American Standard of Fx- 
cellence. He cannot very well do business without one, 
