If you really want deer to benefit from them and grow larger racks, not just get larger bodies, buy mineral blocks that are actually for deer. If you go to your local feed store and buy a salt block or mineral block for livestock, it may help, but they are ment for gaining weight, not groing larger antlers. I'm not saying that they won't help, because I know salt blocks attract them, and mineral blocks that my uncle uses for his cattle get tore up, but I still use ones that are for DEER because I figure that is what they are for, so why not.