I had the same thing happen to me a couple month ago. It just swooped down about 10 of 15 yards from me while I was feeding and killed my favorite hen and just sat on top of her looking at me. When I got back with the gun it flew away and left the hen.
The 3 S's - shoot, shovel and shut up! Most birds of prey are protected.
I lost a number of pullets to hawks, finally I put that deer mesh over my chicken yard. A few times
of the hawks trying to get the chickens and hitting the mesh pretty much deters them. If the flock is out wandering and they see a hawk,
they make a beeline to their yard.
Do you have a rooster?
A hawk swooped at one of our chickens the other day. My sister was right there, but didn't see the whole thing. The hawk didn't get the chicken; I suspect it's either because my sister was right there or because the rooster chased it off!