I also have roosters, and lots of trees and shrubs as cover, and a barn some of the birds like to visit. It all helps. I've also had times when very determined hawks sit out there waiting for unwary chickens to come out, and they are then way safer in their run and coop! Mary
If I were you, I'd be out there adding a covered run. I started with chickens roosting in my barn rafters, because I was told that it would be fine. After many night time deaths, I learned, and set up a coop. Then a run. Then a covered run, and a coop addition. Then another coop addition...
When we have a raptor visitation, my flock is locked in their safe coop and run for at least a week, and usually ten days or more, until the bird gets discouraged and move on. Your hawk might have been scouting your birds, or rodents and rabbits, which would be a good thing, but don't take...