I have three does that were recently bred , one 15 months, and two that are 9 months. I use Purina Goat Chow complete for grain. How much should I be feeding them a day? I know the two younger ones need extra nutrition since they are really still growing their own little bodies, but that feed is so sweet, that I wonder how much is too much? They also get coastal hay daily and all seem healthy and happy-just don't want to over or under feed the grain.