I hope you don't mind a newcomer jumping in but your situation is similar to mine here in NC.

A couple buddies and I have a couple hundred acres leased from my wife's uncle. When we arrived, the property was infested with poachers (hunters and ATVs). The problem is/was that here in NC, to charge someone with tresspassing, you first have to have the land POSTED. That may be the same way in PA.

It has been a constant battle and the sheriff's office has been called out a few times. A couple times last year while hunting we heard shots on our property. That'll absolutely drive you insane!

If those others that the tennant was talking about have been hunting there for a while, I think you'll have a considerable amount of difficulty uprooting them. If the land can accomodate a small number of hunters, perhaps you should consider trying to meet up with a couple of these guys and try figuring them out. The worst case senerio you could make a informal group with a couple of them so that you would have more control.

I sympathize with you though . . .