Agriculture Reference
In-Depth Information
Chicken Comb Types
A rose comb trait is
dominant
over a single comb trait. That means if you breed a male
or female chicken sporting a rose comb with a single-comb bird of the opposite gender,
they will always produce chicks with rose combs. However, if those chicks mate togeth-
er, you will get 75 percent rose-comb chicks, of which 25 percent will be true-breeding
rose comb (both genes are for rose,
homozygous
) and 25 percent true-breeding single-
comb (both genes are for single, homozygous).
This technique of mating rose-comb birds to single-comb birds can be used to check
the purity of your rose-comb stock. If the breeding is true (homozygous), none of their
chicks will be single-combed; if you get single-combed chicks in that first generation of
offspring, then your rose-comb bird is not true for rose comb; he is
heterozygous
(one
gene for rose, one for single).
Other genes involved in comb-type expression produce pea combs, cushion combs,
walnut combs, and strawberry combs, as well as the distinctive buttercup and coronation
combs. It can be difficult to breed for and maintain the proper shape and comb size of
the most unusual varieties. For example, a true buttercup comb should be connected at
the back, creating a “cup.” With the unique genetics involved, it is not very easy to keep
the comb totally connected all the way around and obtain a true cup.
Coronation combs
present raisers with another challenge. These combs have an en-
larged semi-pealike (three-lobed) comb at the back end of an otherwise single comb.
