I also feed free choice hay. ALthough I suppose if you would need to ration it out - make sure you give them approx a "lap" or "flake" of hay for every one-two goats.
I have a variety of breeds - including some nubians. My nubian does get 2 cups of DUMOR Goat Feed (16% protein) per day. If nursing they get 4 cups per day. They also each get 1/4 cup of BOSS (Black Oil Sunflower Seed) on their feed. (and other stuff like some of my herbs, and also fastrack, but I won't get into that unless you want to know
My Snubian BUCK (and also my other bucks) are only getting free choice hay right now. They're not getting any grain. They only get grain when they're breeding doe/s and/or in rut (in the fall).
Goats love browse (weeds, bark, jaggers, leaves, etc.) so if you have an area full of weeds and jaggers - they'd go to town on that ! Just be careful of poisenous plants !
They also love (and it's good for them) Pine needle branches.
You might already know and do all this ... but I just thought I'd "throw it in there"