There are two requirements for sex links. You have to have dominant-recessive genes set up in a way that the male chicks get a dominant sex linked gene from their mother and the pullets get a recessive gene from their father. With sex linked genes, males have two copies but females only have one.
The other requirement is that you have to be able to see the difference the dominant-recessive genes make in the down. That’s why Black Copper Marans make a poor choice for red sex links. You generally can’t see the difference in red or white because the chick has basically black down. When they feather out you should be able to see it, but not in the down.
He’s not listed in Tadkerson’s Black sex link chart (the second one), but your Black Copper Marans should make Black Sex links with the Delaware and Cuckoo hens. Junebuggena would know how easy it is to see the spot better than I would.
The other requirement is that you have to be able to see the difference the dominant-recessive genes make in the down. That’s why Black Copper Marans make a poor choice for red sex links. You generally can’t see the difference in red or white because the chick has basically black down. When they feather out you should be able to see it, but not in the down.
He’s not listed in Tadkerson’s Black sex link chart (the second one), but your Black Copper Marans should make Black Sex links with the Delaware and Cuckoo hens. Junebuggena would know how easy it is to see the spot better than I would.