I raise Hair sheep and we usually keep the newborns and mothers in the sheep house out of the wind. Sometimes this works, unless it is my stubborn one that refuses to be pinned up seperate. In her case she keeps her lambs with her and uses her body to block them from the wind. If you are asking what the mothers should eat after giving birth, I would suggest Hay, grass, and some grain. If you are asking about the newborns, they will only nurse at first, then they will gradually start tasting what the mother eats. As they get older they will start eating hay and grass. I don't raise goats but they are alot like sheep.
If they are brand new and wet, I use a heating barrel. The barrel light stays on any time the temp is less than about 50 as it stays about 60 in the barrel.
Make sure kid gets colostrum within an hour of birth.