A sharp horny projection on a bony prominence on the inner side of the shank, especially in roosters of some gallinaceous birds; a secondary sex character used in defense.
An area that allows birds to scratch.
All traits except the gonads by which males and females differ externally and in...
The choice of individuals within a population to achieve a defined breeding obje...
The base population within which selection is carried out.
A measured trait or condition used as the basis for selection.
The difference between the mean of a selected group and the mean of the original...