Well, We have about four acres total land, and we're already feeding our tiny rabbitry of two does and a buck only the greenery from that property, even without bothering to plant or cultivate very much specifically for the rabbits. Some is reject or over-mature garden greens that are already being grown for market, while the rest is mostly weeds (like grasses, plantain, nodeweed, galinsoga) or landscaping plants that we had already planted years ago and that turned out after the fact to make good rabbit fodder (especially cordyline, hibiscus, orchid tree). A few things, like small patches of various legumes and a patch of sweetpotato, have been planted or left deliberately for forage, and some things, like banana leaves or sweetpotato vines, are a byproduct of other farm enterprises. I plan to plant more fodder grasses, legumes, and mulberry soon for future use. Occasionally we collect things from the commons or friend's properties when out and about.
We're hoping to get some alfalfa pellets again soon to add to the rations, but more out of convenience than necessity (collecting fodder for two daily feedings is a bit of work, even when multiple people split the duty).
In addition to the greens, they get small amounts of richer foods, usually chopped sugar cane, sometimes bananas, carrots or beets. This is all grown on the property as well.
The only thing we're bringing in is sunflower seeds and rolled oats that we get wholesale, which comprise a small portion of their morning feeding. If forced to do without these, I would try to grow a bit of sorghum, corn, or sunflower seed to replace it, as some kind of grain seems really beneficial, especially for the pregnant and nursing does. We don't need to use very much, so it ought to be very feasible.
Feeding rabbits with few resources is not that hard, as livestock go, which explains much of the appeal. Weeds, grass, and other things that grow themselves can go a long way, and other landscape-type things that require very little input can go even further.
Of course, the whole concept of winter feeding is well beyond my experience, so I can't offer much there...
