228 PRINCIPLES OF POULTRY BREEDING 



if the blood elements which they inherited from their parents are 

 to be given an opportunity for full development. 



Another important factor in the environment is the supply of 

 feed, which must be sufficient in amount, wholesome, and of the 

 right degree of concentration. Instances have been known in 

 which the excessive forcing of mature birds during their first laying 

 season had so weakened their vitality that their records in egg pro- 

 duction were not nearly as high as those of their parents, whereas, 

 after selected mating and breeding, they should have excelled them 

 if conditions had been right. Birds which are kept by man in a 

 state of domestication are dependent upon him for shelter and 

 feed, which largely make up their environment, and a careful and 

 proper regulation of this is essential if the inherited qualities are 

 to be given opportunity for their highest development. 



Functional Activities. — From the time the chick is hatched, the 

 degree of development which it will ultimately attain depends in 

 large measure upon the extent to which it performs its normal 

 bodily functions. The normal activity of an organ increases its 

 power to perform its function in a healthy and normal manner. 

 For example, the blacksmith by the constant use of his right arm 

 gradually attains a greater muscular development in this than in 

 the other arm which does not get this regular and systematic 

 exercise. In a similar way the poultryman may, by careful hand- 

 ling and feeding of his birds and by allowing them sufficient exer- 

 cise, keep them in a normal and healthy condition. Should he 

 restrict their exercise, and increase the concentrated feed stuffs, 

 such as corn meal, the birds would soon become lazy, take on 

 excessive fat, and gradually become poorer and poorer layers until 

 the function would finally cease. If the conditions were not cor- 

 rected, the functional activities of the body would become con- 

 gested and clogged and death would result. 



In the same way it is possible to develop excessively the growth 

 and maturity of certain organs; as, for instance, in the forcing of 

 pullets for early maturity. The egg-forming organs are stimulated 

 to activity before they attain their normal development, and the 

 resulting eggs are small in size, in many instances containing weak 

 germs, especially if the pullets are mated to males of early devel- 

 opment. Their eggs when hatched will produce chicks small in 

 size and of light weight, many of them cripples and weaklings. 

 Not only will the eggs be small, but the bird itself, because of its 

 early maturity, will never attain the size and shape which would 



