Is this straight grass hay? What kind of grass? Is it leafy, or quite stemmy? Is it nice & green, or very dry & almost brown? Any dust?
I wouldn't go by "most of the horses in the area are eating this"--right here in my neighborhood I can name several horse owners who are feeding their horses terrible hay--Some of the hay I haul away to the dump is in better shape than what some of them are feeding. These are big horses that these people own--and I suppose they get absolutely nothing else (not even any grain) so they have to eat or totally starve. I've gone to look at hay and turned it down because it was moldy--very moldy, not just a little musty--and yet the guys were selling that same hay to umpteen other horse people.
I've got some fine grass hay here that the horses absolutely don't like. They will pick out the bit of alfalfa that is in the hay and then leave the rest--they figure that it makes great bedding! I had some brome hay earlier that one horse absolutely refused to eat. Another liked the stuff, and some of the others ate it only when they had to--they wanted some alfalfa mix instead. It's rare for us to have hay that no one will eat, but definitely some of the horses are more fussy than others.
I'm not sure how many horses you have? If it's just a few then it may not be surprising if they "all" refuse certain hay--even several different batches from different suppliers if it is all a similar type of hay. If you've got quite a herd then I woud expect some of them would eat any given kind of hay--even if it's quite poor and they don't eat much of it, I'd expect some of them would pick through it.