Although....the white horse looks like it has its head shoved...well...until you notice it under the other horse anyway. A variation on the "pole growing out of the head" syndrome.
Ahh... I never looked at it quite like that before, but you're right, the white horse does look like it's got it's head shoved... well, I guess you know.
One good thing about the white horse is that it allows the detail of the other horse's tail stand out. That would have been lost if the white horse wasn't there. Or maybe it could be the first breed of 8-legged horse?