Matt, I had the same question a wrok the other day anda guy at work who seems to have good answers told me that the bigger bucks breed longer into the year than small ones do ( dominance, more second rut activity than the little guys) so he said the big ones have moretestosterone (sorry my spelling sucks) in the system longer and that is why the big guys keep the gear longer. He said when the testosterone drops off that is whattrigers sheding. Makes sense but not saying he is right.