BREEDING 135 



With meat practically a by-product, and the whole carcass 

 the retail market unit, the question of a meat type is not so 

 important as in the case of beef cattle. There, meat is the 

 principal product, and there is a great range of value between 

 the various cuts. These cuts are sold separately, and are, 

 in point of fact, the retail market units. The proportion 

 between the more and the less expensive ones in the carcass 

 makes considerable difference in its value. Different por- 

 tions of the poultry carcass are not given different market 

 values. It is the general condition of the whole carcass, that 

 governs its desirability. 



Constitutional Vigor and Hatching Power. — Williams^ 

 found that in choosing four Black Langshan hens for their 

 strong vitality, and comparing them with four others of 

 the same breed that were lacking in vitality, 62.95 per 

 cent, of all eggs laid by the vigorous birds that were 

 incubated hatched. On the other hand, only 29.27 per 

 cent, of the eggs incubated from those laid by the hens that 

 were noticeably weak hatched. 



In tests involving over three thousand eggs from White 

 Leghorns and over one thousand from Barred Plymouth 

 Rocks, Rice and Rogers^ found that the average fertility 

 of the eggs from flocks selected for their good vitality was 

 7.5 per cent, greater and the actual hatching power was 7.6 

 per cent, greater than in the case of eggs from flocks of birds 

 that at some time had exhibited signs of weakness. 



Hatching Power. — Second to constitutional vigor in impor- 

 tance as a point of selection, only because it depends upon 

 it, is hatching power. If constitutional vigor is the conductor 

 which connects the generator with its motors, hatching power 

 is the switch that closes the circuit. Without it production 

 ceases. With the average period of profitable production 

 but two years, the necessity for the ability to renew 

 the flock each year with a fair degree of certainty is 

 obvious. 



Assuming good vigor, actual infertility, by which is meant 



• Bachelor's Thesis, Oklahoma Agricultural College, 1913. 

 = CorneU Bulletin No. 318. 



