Non ruminants can't digest things like goats or
cattle, because of this even the browser donkey will be picky about what they eat.
Our donkey loves grasses, tender branches except for oak are on the dinner plate (fruit trees except for Figs are apparently a real treat).
She will bypass many of the weeds and tough grasses but she does a fair job of keeping the pasture areas mowed, leaving just the tough, woody plants for me to scythe down.
Our donkey is free range, no fences for her as yet. When we do
fence some areas for her, she will get about 1/4 acre per day to munch. I came up with this size by watching how much she grazes down every day.
If we had more than one, I would have to increase the size to 1/4 acre per animal per day I think.
Over seeding with those plants your animals cherish is a good way to get rid of the nasty, non palatable weeds, just mow close and over seed heavily a few times to make sure those undesirables are shaded out.
Wheat is great for winter greens for horses and donkeys, it will grow to around 8 inches tall and regrow every time they eat it down, in the spring you can let it go or they can keep eating it and it will then die out because it has been clipped close when it needed to grow tall.
Redhawk