We lost a hen to probably a hawk a couple of days ago. We just started free-ranging them the day before. They had hardly come out of the barn their coop is in the first day, and the second day, barely left the safety of the barn, and the roo was with them, after 20 minutes we go out and do a headcount, one missing. No trace. No feathers anywhere, no blood, nothing. We looked all over the place for hours, didn't find her.
We're going to be making a chicken tractor this week for them before we let them out again. The poor things hate being left inside and try to get out of the coop every time we go feed or water them or collect eggs.
We have free-ranged our guineas and Pekin ducks for months without any big hawk problem, though we do have tons of them flying overhead and occasionally landing in the trees. I bought a "MegaBlast" whistle thing in the novelty toys at
Walmart. It was 88 cents. It makes a really loud noise, and my kids go out and blow that every time they see a hawk coming close. The hawks wing it away quickly. They stay farther away now we've got that, but we had the chickens free-ranging out back and couldn't see them or any hawks checking them out.
I think a regular whistle might help scare the hawks away, too. I just whistle really shrill if I'm out there and see a hawk, and they always turn around and fly somewhere else. I can whistle pretty dang loud and shrill, so I don't need the hawk horn, as we call it, but if you just find something loud and annoying, you might try that to scare them away. Even a child's cap gun might work.
We live way out in the country, lots of fields and woods around us, so prime hawk area. We won't be free-ranging the chickens anymore. They're just not bright enough to avoid the hawks, I think. Our ducks seem to be way too big for a hawk to try anything with, and the guineas make their own loud noise whenever they see a hawk, plus they're good at knowing to run and hide. Our chickens might learn that with time, but I'm not going to take the chance of losing a bunch of them while they learn. We've only got seven hens and a roo, not enough to take losses on without some effect.
Good luck with keeping the hawks away!