Rutting fallow bucks for example, will fight anything. Including a dead deer. I have deer and have seen it. Bucks with antlers often kill each other or themselves. Leave loose wire anywhere and they will find it and fight with it. Same with hay bale netting bits buried anywhere. Bits of wire. Rope left on a gate, great to fight with, wrap it around your antlers, around your neck and strangle oneself and hang their. Another ffffing breeding buck gone after years of selective breeding ... Snakes, other deer etc. Leave a carcase in the paddock and anyof the boys will fight with it. Even a stinky old carcase left too long. Doesn't have to be the rut either.