Interesting to hear about them from someone more local. I tend to dismiss them a bit as a USA problem. My hens also do that same noise and statues routine when something spooks them from above. So far its only been a kite though not a hawk and he has just watched.
Yeah, I had never really taken much notice of them till I got chooks. We have a very large owl, nesting sea eagles, goshawks, swamp harriers and the occasional visit from a wedge tail.
Seems to me the words has got around, " they keep chooks at inlet farm "