I have 10 acres total; one 5 acres is fenced and cross-fenced, and contains all of the 'development' on the premises--the other, adjoining 5 acres is fully perimeter fenced. There is a faucet on the fenceline that serves the other 5 acres. I have 8 miniatures and one 'fullsized' APHA mare, along with my dogs.
'Development' means the house, barn, outbuildings, crossfencing, runs and pens, and run-ins, and a large(125' X 250') arena, pipe fenced(and the most useful asset of the place-great for driving! ) My place does have grass (no irrigation; native and soil-bank-planted grasses-wheat grass and grammas, mostly), but in the high desert, native grass is fragile and if overgrazed, would permanently disappear, leaving only weeds, and dirt to blow away(which has happened to a LOT of this part of the country, because people think if they have ANY acreage, they can turn everything out on it all the time-which ruins the country.) IF/WHEN we have enough rain to allow it to prosper, my horses get to graze a bit; otherwise, they live in dry lots. I use nearly all of my horses, driving, so they get exercise that way; but I am a FIRM believer in giving them PLENTY of 'moving around' room at all times, so their runs(and stalls and sheds) are roomy, the multiple horse pen is large, and there is the arena, for turn out. Actually, I am just as glad that I DON'T have pasture; I have much less concern over parasite load and nutritional issues such as obesity and founder-just my personal position. Where we lived before this, we had @ 6.5 acres of irrigated pasture-it was great for the big horses, but to keep them from becoming hog-fat, I still had to limit their turn out time--and I didn't have minis then(28 years ago), and have often been glad I didn't, under those circumstances! Again, just my personal take.
Margo