I have spent a lot of time studying color coat genetics. I would be happy to answer any questions you have. however, there is no such thing as a black chestnut. the E gene controls if thehorse is capable of making black hair, if it is ee then it is chestnut, if it is Ee or EE then it is black. the A gene controls if the black hair is restricted to the points, this makes a bay. I hate to burst your bubble, it would be cool to have horses that change colors like that, but it just dosnt exist. I do love the creme and dun genes though!