Our run is pretty large, way too big to just drape netting over, so we strung piano wire across from corner to corner, kind of in an X over the run, and my husband put some kind of turnbuckle type things that we can turn to keep the wire tight. Over that are lengths of chicken wire, with the edges "sewn" together with wire, so that it makes one great big wire mesh cover. All the edges are turned over wooden beams at the top, and fastened down, and connected to the fencing that makes the "walls". The piano wire (or something like that; that's what it looks like to me) is tight enough to keep the chicken wire from drooping and sagging. It's tall enough that we can walk around in there without ducking. I do hope a hawk doesn't try to crash through. It might break it's neck or something.