Kind of what rybohunter said, it's right next to impossible until they get older. Where I hunt I don't give a hoot until they get to 3 1/2 years old anyway, and I think I can identify those bucks from year to year with about 90% reliability. First, there just aren't that many bucks that make it to 4 1/2 y.o., andoften they have some unique antler characteristic by then. At that it isn't an exact science.