THE PROBLEMS IN MATING AND IN EGG PRODUCTION 103 



individual records than was the case with those not inbred. 

 The vigor of the laying stock as shown by the mortality rec- 

 ords was lowest in the inbred stock. The vigor of the off- 

 spring as shown by the mortality records of the chicks was 

 lowest in the inbred stock. There was a lower fertility of 

 eggs in the inbred stock. 



Sterility of hens is often due to a closure of the anterior 

 or funnel portion of the oviduct, or to an adhesion of the lips 

 of the funnel. In all such cases the sex organs pass through 

 the same changes from non-laying to laying condition as in 

 the birds which actually produce eggs. When the eggs cannot 

 enter the egg canal they are discharged into the body cavity and 

 absorbed. If they enter the duct and the duct be obstructed 

 they may be returned and fall into the body cavity. If 

 the duct is ruptured, the eggs pass along the canal, developing 

 normally till they reach the rupture, then pass into the body 

 cavity. A large number of eggs may be absorbed from the 

 abdominal cavity without causing any inconvenience to the 

 bird. One abdominal cavity examined showed all stages of 

 absorption of such eggs, and a large mass of shell membranes 

 were found in the cavity. The ovary of this bird was the 

 same as the ovary of any laying bird, containing a normal series 

 of developing yolks. 



Prepotency is the ability of the parent to fix his characteris- 

 tics in the offspring. 



The male should not only be pure bred, but have the purity 

 of breeding that extends to a high degree of egg laying. 



Prepotency does not always follow blood lines. One in- 

 dividual may be prepotent and another of the same blood 

 line or of the same parentage may not. But an individual 

 bred pure to a certain type and other essential characteristics 

 for many generations is more hkely to transmit his character- 

 istics than one that is not or is simply a "grade." 



The reasons of the above are explained by the Mendelian 

 law. 



Some characters segregate, others unite or blend. The 

 eggs produced by a cross bred hen, for example the progeny of 

 a Barred Plymouth Rock and a White Leghorn cross, usually 

 show the influence of both parents. That is, they have neither 



