260 PROFITS IN POULTERY.. 
The objection to crosses repeated every year is that no 
progress is made beyond the first year, the cross-bred 
males not being desirable for breeding. By grading up 
the flock, however, this difficulty is avoided. Males of 
the same breed are used each successive year, and the 
flock each year becomes more like the pure breed, until 
at last it is practically identical with that breed. But 
being a cross and containing some outside blood, and no 
inbreeding having been practiced, the hens have fine 
vigor and are an improvement on the pure breed. 
