Well, as an upsate for all who read the post about the horse we had die on us after only 2 days of having him, and with no apparent reason as we could see. It had baffled us for a while, and we finally have an answer.
Apparently he had a blood clot that moved to his brain. This would explain why he stumbed around and didnt die immediately, etc.
*sigh* it sucks that it had to happen, but atleast now we know why. RIP Canvas Master.