I dont have chickens in town but we have a house in inglewood and see hawks FREQUENTLY we had one eating a snake in the back yard one day. Now my farm neighbor has never had a chicken taken by a hawk and she free ranges all her chickens and we have several pairs that live in the woods nearby. They are all over now. Just would have to watch them.
Our resident red tails are less of a threat than the migration that comes in Fall. Around October, we have many, many more than usual and they are hungry and bold. The trees are simultaneously providing less cover. That was how I lost by biggest Welsumer hen when I ran in the house for a few minutes. She was under brush in the forest where you'd think she'd be at low risk. I saw the hawk responsible when I came back and it was reluctant to leave even with me yelling and throwing stuff at it. Pretty sure it was a Northern Goshawk by size, coloring, and the long tail. My Wellie's neck was broken -- that hawk knew how to make a kill. I've had two other attacks in the yard by juvenile red tails. One was thwarted by a rooster and the other simply couldn't get a good hold on a loose-feathered puffball. Both escaped with only a fist full of pulled feathers. I range under pretty close supervision and still can't prevent losses to raptors.