r I .Y MOUTH 1WVK STANDARD A\D HlfUUn HOOK 51 



it is possible to select for strength and vigor as well as any other 

 quality. In many cases stamina is the first and most important 

 consideration for selection. Usually, in-breeding, if too long 

 continued, results in loss of vitality, which is indicated by in- 

 creased infertility, slower growth, smaller size, delayed feather- 

 ing in the young, and after a time by weak and twisted feathers 

 in adults. These highly undesirable qualities appear so gradually 

 and increase in intensity so slowly in succeeding generations that 

 they often diminish the value of many a flock very appreciably 

 before they are detected. 



Out-Crossing. When such a condition is found to exist the 

 only remedy is out-crossing. This consists, of course, of intro- 

 ducing the blood of some other line or strain into the flock ; an 

 expediency that is accompanied by danger of losing qualities 

 that have been gained by several generations, perhaps, of in- 

 breeding. There are, however, several modes of introducing new 

 blood, some of which are accompanied by great risks, and others 

 that, though somewhat slower in operation, are comparatively 

 safe. New blood can be very quickly introduced by using a 

 male of an unrelated line. The effect, as far as restoring vitality 

 in all its phases is concerned, is almost magical, and usually, it 

 is fully as efficacious in destroying the very characteristics to 

 establish which in-breeding was practiced too long. Unless a 

 male from a strain that possesses very closely the same attributes 

 that have become so strongly established in the first strain can 

 be secured, the introduction of new blood through the male, 

 directly, is experimental, to say the least, and the results cannot 

 be even approximately foretold, because even though the first 

 out-cross produces specimens that are satisfactory, the second 

 generation . is very liable to prove disappointing in breeding 

 prowess. 



It is much safer to proceed slowly and cautiously. One safe 

 mode of out-crossing would be as follows : a male of an unre- 

 lated line (B) may be bred to a few females of the first line 

 (A) and the female progeny of this mating (BA) mated back to 

 males of th'j first line (A), and so on for as many generations as 

 seem advisalVe, using the female progeny for new blood, until 

 the results are satisfactory, when the progeny may be recrossed 

 with the original line, both ways. Occasionally the results of the 

 first cross will be so pre-eminently satisfactory that males from 

 this cross may be used upon the original line, but only in case 

 the results are most satisfactory and even then it is better to 



