How big is a 2 1/2 year old bison? I am looking for a really, really large bison, (like the kind you put on the wall that make people say holy #@$!!!!) lol. Whatage of bison doI want here? I have found a couple hunts that offer from 2 1/2 year olds to 5 1/2 and older. Is a 2 1/2 year old small?