Quote:
Black Roo and chocolate should make just black... if your male has a chocolate gene it will have 50% black and 50% black with the chocolate gene.
(It's what I have written in my book anyway lol )
Chocolate (choc) is sex-linked recessive. Chocolate is like gold and silver, the male can have two doses and the female only one, because its on the sex chromosome. So a chocolate cock has two doses of the chocolate gene to express it (its recessive so one dose wont express!) and the female needs only one dose to be chocolate to express it.
The counterpart of sex-linked is called autosomal, that means on both sexes the same expression of a gene.
Dun colour is autosomal, it looks/acts the same on the hen and the cock. Dun colour is a bit of a weird gene because its located on the site where dominant white is located too. Dun colour is an allele of dominant white.
Best comparison of Dun is with blue. One dose makes the dark brown dun, hobby name "chocolate" in some breeds like Old English Game Bantams and Polish. Two doses make dun splash, hobby name khaki. Dun color breeds as follows:
Most breeds called "chocolate" in the U.S. are relay Dun.
Chris