Ugh, sourcing the hay would be a pain for me. I suppose the local nursery might get some, but not at a nice price, I suspect. Might have to find an alternative.
Tell them you don't want the good stuff, you want the old stuff. Usually folks who sell a lot of hay, have a few rolls that are sitting out back that they either couldn't sell or the binding didn't hold up so they couldn't move it well.
They're usually pretty happy to get rid of it for $10 bucks a roll or so. Worth a shot.