A DUAL PURPOSE TYPE 



29 



definitely states that high egg production is not carried on at the 

 expense of breeding power. He writes: 



We have no evidence to show that heavy egg production in a normal, healthy 

 bird will exhaust her strength and vitality. There are, of course, many hens that 

 fail to stand up under production, but invariably we find their failure is due to a 

 general lack of vitality and inherent vigor. We have made a careful study of fertility 

 and hatchability as correlated to egg production, and we find absolutely no relation 

 between heavy and poor fertility and low hatchability. In other words, we find just 

 as much poor fertility and low hatchability from low producers as from high pro- 

 ducers. We quite frequently find that pullets from high producing hens do not 

 produce nearly as well as their dams, which, of course, is just what we expect through 

 the influence of Mendelian segregation of characters in the progeny. In other words, 

 if a hen and the male to which she is mated are high for production, we conse- 

 quently get pullets, all of which are high producers. On the other hand, if they are 

 impure for high production or, expressed another way, impure for winter produc- 

 tion we get progeny representing various degrees of production. 



The method of inheritance of fecundity, or the laying tendency, is 

 discussed in Chapter III. 



Farm Flock of Purebred Barred Plymouth Rocks. 



On the farms. The type that makes good as a farm fowl is the 

 dual type. While in especially bred strains of the American breeds 

 either egg or meat values may be developed to a point where the 

 stock is comparable with that of highly specialized breeds, in the 

 last analysis it will be found that it is a satisfactory combination of 

 the two prooerties as found in the American breeds that makes them 

 a well balanced type for general purposes. There are those who will 



