242 PRINCIPLES OF POULTRY BREEDING 
There is also a relation between the color of the comb and 
wattles and the health and vigor of the bird, the latter being asso- 
ciated with a bright red comb, and disease or lack of vigor with 
a dull color or lack of color. 
In different breeds there is a definite relation between the size 
and weight of the body and the development of wings. In the 
lighter breeds this results in powers of flight which are lacking in 
the heavier breeds. 
Many false notions as to correlation are often advanced. For 
instance, there is a belief that the color of the skin indicates the 
quality and flavor of the flesh; that the color of eggs hells influences 
the quality of the contents; that white birds are often of weaker 
constitution than pigmented birds,—all of these are without sub- 
stantial proof. 
Body Character and Functional Activity—Poultry breeders and 
experimenters have for a number of years persistently endeavored 
to find some correlation between egg production and some readily 
detected external characteristics, but with little success. As was 
previously stated, egg production seems to be an inherited func- 
tion based on the gametic constitution of the individual, and has 
not been consistently indicated by any other factor. A bright red 
comb, full bright eyes, erect carriage, compact and solid body are 
all signs of the vigor and vitality which are necessary for heavy 
egg production, but none can be said to be always associated 
with it. 
The author has noted a consistent relation between shape of 
barrel or body and the power of reproduction. Heavy egg pro- 
duction was found to be associated with great depth and breadth 
of body in proportion to its length. There is need for much 
statistical work to test such a relationship, and accurate results 
cannot be claimed until a great number of individuals have been 
studied. Wherever it is possible to associate certain external 
features with functional activity or vitality or constitution, it is 
a simple matter to put into practice a rigid selection,—using only 
birds which show this external character. 
Prepotency.—By prepotency is meant the increased power 
which one parent has over the other of imparting its characteristics 
to the offspring. It is really the power which an individual has 
to transmit its own characteristics. This question of prepotency 
is of the utmost value to the breeder, because of the direct influence 
which it is bound to have upon the improvement of his flock, 
