hm... very interesting topic...
i currently have 3 adult bucks, 3 adult does, 3 jr does, 2 jr bucks, and 14 kits that are 7/8 wks old. so a total of 26.
i cut lots of grass with a machette (the big jungle-choppin through knives haha) and i cut it into an old plastic kitchen trash can. i still feed pellets but you can definitely tell when i dont cut grass for them one day with suddenly empty feeders hahaha.
but for this amount of rabbits i go through about 3 50# feed bags sorta packed full of grass. of course i have alot of land and there is plenty that never gets mowed or anything. so right now i've got a sort of field of my own that only i cut with the machette for the rabbits. right now it is about knee high. so once i get cut across that area i should be able to go back to the other end and start back there with tall stuff that has grown back in.