Sex links are when you can tell the sex of a chick at hatch based on sex-linked genetics. A rooster gives one copy of all his genes to all his offspring. A hen gives one copy to all her sons but does not give a copy of all her genes to her daughters. The ones she does not give to her daughters are the sex linked genes. If these genes are reflected in the chicks when they hatch, you can sex the chicks if the parents are set up properly. The rooster need to be "pure" for those genes. That means that both genes at that critical gene pair are the same and are the recessive version. Some breeds are auto-sexing, that is different.
One example is red sex links. If the father is pure for the recessive gold gene and the mother has the dominant silver version of that gene pair, the male chicks will have yellow down and the females will have red. The other part of this is that you have to be able to see this difference. You cannot see this difference on a solid black chick, red or yellow down just doesn't happen. With certain chickens this difference may be only a small spot on the head. Not every gold male over a silver hen will produce a red sex like, sometimes you cannot see the difference in the down.
Another example is feather sexing. If the father has the recessive fast-feathering gene and the hen has the dominant slow-feathering gene the offspring will hatch where the wing feathers of the pullets are longer than the wing feathers of the males.
There are other ways. You can do this with certain leg colors. There are probably some I can't remember.
The one Aart is talking about uses the sex-linked barring gene. If a rooster with the recessive non-barring gene mates a hen that has the dominant barring gene, all males will be barred and no females will be barred. You can see this barring as a white spot on the male chicks head at hatch. The females will not have this spot. Thee are called black sex links since most of these chicks are black. The hens usually used to make black sex links are black barred like cuckoo marans, dominique, or barred rock. You can use a non-black barred hen like your creme legbar but she has to be mated with a rooster that will cause a down color where the spot can be seen. I don't know if you will be able to see the spot on a Black Copper Marans rooster over a Cream Legbar hen.
One example is red sex links. If the father is pure for the recessive gold gene and the mother has the dominant silver version of that gene pair, the male chicks will have yellow down and the females will have red. The other part of this is that you have to be able to see this difference. You cannot see this difference on a solid black chick, red or yellow down just doesn't happen. With certain chickens this difference may be only a small spot on the head. Not every gold male over a silver hen will produce a red sex like, sometimes you cannot see the difference in the down.
Another example is feather sexing. If the father has the recessive fast-feathering gene and the hen has the dominant slow-feathering gene the offspring will hatch where the wing feathers of the pullets are longer than the wing feathers of the males.
There are other ways. You can do this with certain leg colors. There are probably some I can't remember.
The one Aart is talking about uses the sex-linked barring gene. If a rooster with the recessive non-barring gene mates a hen that has the dominant barring gene, all males will be barred and no females will be barred. You can see this barring as a white spot on the male chicks head at hatch. The females will not have this spot. Thee are called black sex links since most of these chicks are black. The hens usually used to make black sex links are black barred like cuckoo marans, dominique, or barred rock. You can use a non-black barred hen like your creme legbar but she has to be mated with a rooster that will cause a down color where the spot can be seen. I don't know if you will be able to see the spot on a Black Copper Marans rooster over a Cream Legbar hen.
