Examples:

I'd say 30-35k a piece :)

Lovely pieces :) I would suggest outlining. Not completely outlining the whole horse because I think that can make it look really unrealistic, but just parts of the horse that blend in with itself/background. So on your first piece the right side of the horses jaw blends in with the neck because it's the same color. You could take that shadow color and outline his jaw to really define the shape of his head. And the same with the last example to help his head kinda 'pop' away from his front legs instead of mixing in with them. The left side is good with the dark outline against the white part of his leg, but the right side doesn't have much separating his head from his leg