102 MY POULTRY DAY BY DAY 
processes of artificial selection—that is, man’s selection—be 
rendered into new varieties most readily. When one can fix the 
type we call it a pure breed. 
One occasionally gets a “‘ reversion,” or return to type, from the 
mating of pure breeds, especially if the male and female be two 
distinctly separate inbred strains. It would seem as if a certain 
relationship—remote but true—were necessary to preserve the 
type in its purity. 
What one must guard against is indiscriminate inbreeding with 
one’s own stock. While new blood is essential at times to main- 
tain vigour and health, it need not be a violent outcross. 
For the amateur or the average poultryman it is only essential 
to know a little of the first principles of breeding. So long as he 
introduces good pedigree birds from the scientific breeders such as 
I have named, he cannot go far wrong. And while the pullet actu- 
ally produces the eggs it is the male bird chiefly that determines 
the numbers thereof. No money within reason is too much to 
pay for a cockerel from a deep egg-laying strain. The voice of 
an expert should be heard on this important problem, and no one 
is better fitted to speak than Mr Duncan Forbes Laurie, an 
Australian scientist who wrote in The Poultry World: 
“There are two methods possible and advisable in introducing 
new blood : 
““No 1.—New blood may be introduced by means of a male bird 
guaranteed to be the son of a high laying hen whose eggs were 
large. Mate with your own single-tested hens. Then single-test 
all pullets to be used as breeders. Reserve sufficient cockerels 
while you test the pullets. As you had hens which were good 
layers to breed from, the cockerels from this new introduction will 
inherit laying from your own stock and will transmit this good 
laying to their pullets (daughters). 
“No, 2.—Is by means of purchased pullets which are to be 
single-tested before they are bred from. Then mate all which 
satisfactorily pass the test with a suitable male bird from your 
own stock. The progeny, both sexes, will be reliable. Note, 
