Above advice is great. With raptors, it's about assessing risk, at least for me. I have hawks in my neighborhood. I only free range my small flock when I'm with them. Over time (about two years) I got more confident and would move around the yard further, sometimes running in the house for a minute or two. That ended last week when the hawk attacked my girls. I was right next to the tree where the hawk tried to pick off one hen on a low branch. Fortunately, the hawk did not succeed.
I figured it would happen one day and I'm fortunate the hawk did not succeed. The girls have been in their well-protected run ever since. I'll let them out again, but will stick very close to them.