I would kill the Copperheads but let the rattlers go as the Timber rattler is protected anyway. I once caught a Timber rattler with my bare hands and kept it in a cage in my living room for a while before releasing it back into the wild. I have caught and kept snakes for years in my younger years, now I only catch black snakes around my house and I have plenty. My house was built in the 1800's and the snakes seem to like it here.