POULTRY-CRAFT. 153 
4 
by a male of another variety cannot be depended on to breed true. It is only 
in rare instances that eggs laid ten days after contamination hatch chicks 
which show in any way the influence of the foreign male. Few, perhaps 
none, of the reported cases of the influence of a male of another breed 
persisting for months or years, rest on indisputable evidence. The same 
thing may be said of alleged cases of ‘* mental impressions.” 
212. Introducing New Blood.—Inbreeding.—It is commonly believed 
by poultrymen that to maintain the vigor of a stock new blood must be 
frequently introduced. Many go so far as to say that any inbreeding at all is 
bad; that it is from the outset the beginning of deterioration. If a man 
inbreeds, and his stock is weak, the weakness is invariably attributed to 
inbreeding. Most of the evils assigned to inbreeding are not due to 
inbreeding, but to careless selection. There is no evidence that the breeding 
of males and females of the nearest kin necessarily initiates degeneracy. 
There is abundant evidence that with proper selection for stamina, and to 
avoid common defects, very close inbreeding can be followed for a long time 
without injuring the stock. There is also abundant evidence that breeding 
unrelated fowls without careful attention to vigor, and avoidance of common 
defects, is at once attended with precisely the same results as breeding fowls 
of near kin under the same conditions. The prejudice (for it is nothing else) 
against inbreeding, is one of the serious drawbacks to general improvement 
of poultry. A breeder who does not confine his matings within narrow blood 
lines slips back about as fast as he crawls forward. Nearly every new 
breeder wastes a number of years trying to breed good stock without 
inbreeding. Practical poultrymen will notably improve their stock by 
inbreeding, then throw away results by bringing in new blood because of the 
fear that they may carry inbreeding too far. In time nearly all breeders come 
to admit that inbreeding is absolutely necessary (in breeding fancy fowls) in 
color breeding, yet few can be found who do not think it unquestionably bad 
for the practical breeder. As has already been said, there is not one law of 
breeding for one class of breeders and another for another class. If 
inbreeding is necessary to fix superiority in color, it is necessary to fix it in 
shape; if it is necessary to fix it in shape, it is necessary to fix superior laying 
capacity or rapid growth, or vigor. Inbreeding is necessary hecause there 
cannot be intelligent breeding without inbreeding. One who does not breed 
within close lines cannot £zow his stock as far back as he must know it if it 
is to be mated with reasonable assurance that the matings will produce the 
desired results. To secure uniformity inbreeding is necessary, because the 
number of inheritable differences must be kept as low as possible, and this 
can only be done by close inbreeding. The vigor of a flock is sustained not 
by regularly introducing new blood, but by selecting breeding birds for vigor. 
Vigorous birds generally beget vigorous offspring ; weak birds weak offspring, 
whether akin or not. 
