376 COMMERCIAL POULTRY RAISING 



they originated should convince any one that this is a bad plan. 

 The first cross is not so bad, as a rule, and occasionally it possesses 

 some slight advantages in egg production or weight, but these 

 hybrids should not be mated in any way, either among them- 

 selves or back to their parents. Therefore, to continue cross- 

 breeding it is necessary to maintain two distinct pure breeds year 

 after year, and to destroy the hybrids as soon as they cease to be 

 profitable. This occasions many separate houses and yards, 

 for the sexes of each pure breed, and for the crosses, a practice 

 that is both expensive and troublesome. 



Grading Up Mongrels. — Sometimes it is profitable to grade up 



(Courtesy Maryland Experiment Station) 

 Fig. 247. — " Busy moment for the trap nests." 



a flock of mongrels, such as are found on many general farms, 

 by introducing pure bred males. Pure bred males of the same 

 variety should be used year after year, however, and not the males 

 from the offspring of the first cross. In the course of four or 

 five generations, with careful selection, it is possible to grade up 

 the original flock of mongrels to the level of the pure bred male 

 in appearances, but scarcely in breeding qualities. There is 

 always more or less chance of a reversion to type in breeding 

 from mongrels, hence it is often cheaper in the long run to com- 

 mence with pure bred stock. 



Barnyard fowls are better than none, of course, but why keep 



