I can't find the unicorn in Red Dead!!!?

I know where your supposed to find it (that area above torque-whatever where the hungarian half-breds were). Ive combed through that whole area at least 5 times on different days and i cant find it! Yes i killed the chupacabra (although in a completely different location). I even looked around the area of where i killed the chupacabra although not as thoroughly. WHAT AM I DOING WRONG?? Im getting really frustrated.