Could you comfortably have on 6 acres and have enough grass for summer & winter bearing in mind they would be out all year round unless the weather was really crap.
Well, at my yard two horses (Doug and Romeo) are out all year on a very very very small section of the field, around the size of my garden
Theyre both on strict diets and this is fine for them. I think you could have 6 - 7 horses personally (yes, one horse per acre blah blah) if you rotated the ponies around etc etc
Depend on the field and how it drains etc, but I'd say 4 as a very rough guess.
I've got under 3 acres, but it's good grazing and more than enough for my 2. At the moment I could easily fit another 1 if not 2 on it! It makes it far too tempting to want another one!