I guess what you're asking is about culls..?
I don't cull deer unless I have pictures of them and have decided that they are in fact a cull. For me to have decided that, they must be at least 3 years old and look as if they will never make theirselves into a 125 inch deer... whether that be because of an injury or just horrible genes, such as not putting on anymore points than a mainframe 6.
By the way, what part of MS are you from?