We are in Kentucky. Have 5 acres w/ house, barn and small arena on it. Everything else is in pasture and we buy hay. Found it is much more cost effective that way. Even if you get farmers to hay it for you they either want 1/2 or charge you for their work. Might as well put that money towards purchasing extra hay and let the horses use the fields. And no matter which way you go you still need to fertilize, lime, and weed control.
We have a dry lot that connects to a tract around our pasture. It lets the horses get a lot of movement while dry lotted but keeps them off the grass when we don't want them there. The term paradise paddock I think is what a set up like this is called - you might want to look it up.
We have our pastures divided into 2 pastures, and a smaller 3rd side pasture due to how our land lays around the house. We rotate the horses on these lots for best maintenance of grass.
Here in KY - I can maintain 4 horses on 4 acres (about what we have in pasture) from May - November with no extra hay. As long as its not a drought year. The rest of the time time I supplement with round bales. It takes managing the land, but it can be done in the right locations. I've even had more equines on this land and been able to maintain with just minimal hay supplementation through the summer as well. But the more animals per acre - the more work it is to keep usable pasture.