[PoochtheMighty]

I am probably being repetitive here, but the color of the hoof actually does not matter; it's kind of an old wive's tale that white hooves are stronger than dark hooves. I have a paint cross and I have asked all my farriers the same question. Each one said the same thing; it makes no difference.

As far as size of the hoof goes, too-small hooves have a higher chance of leading to navicular disease, I've heard. However, horses with hooves that are too big could most certainly have problems as well. As has been said, the hoof size is irrelevant as long as it is proportional to the size of the horse.