I don't think this is workable.
The zoning in my area is 3 acres for the first horse, an acre for each additional horse.
I have 5 and a half acres split in two paddocks and 2 1/2 horses (the half is a 10.2H pony who weighs aprox. 350 pounds, he's really 1/3 of a horse), animals are out 24/7 and I rotate and drag pastures. I consider this the minimum to keep decent grass and not to have to pick manure, and I am in a warmer climate with a longer growing season than you.
5 horses out in 2.5 acres, no matter how you rotate, are not going to have any grazing and are going to reduce each section to a dirt lot pretty quickly. And 1 bale among 5 horses per day is no where *near* enough forage, it should be 1/2 - 2/3 of a bale per day per horse. Or did I misunderstand and are you giving *each* horse an entire bale?
Also, that number of horses in that small of an area will produce more manure than can be managed by dragging and rotating, you will have to pick manure out of the paddocks.
To make this workable, you will either need to decrease horses, increase pasture acreage, stable the horses at night or all of the above. Even with intense pasture management, meaning "sacrifice" area, rotating, removing manure, seeding and fertilizing, I'm still not sure you'll end up with any grass with this many horses on that acreage.
Last edited by maura; 05-11-2012 at 06:08 PM.