Deb, I like that frozen peas idea too. Besides not wanting to actually injure the bird I'm in suburbia so rocks or clay balls would be putting my neighbors windows at risk.
I won't be killing any hawks. Besides being illegal I just admire them too much. I did lose a hen to a Red-Tailed Hawk about 6 months ago. I put up a few more hides for the hens after that but Coopers are awfully agile. I'm not going to fault either bird for doing what it's designed to do. In a way these close encounters have been really amazing.
Bryant, thank you for the fishing line idea. I have some predator net to put up but the trees in the run were making it difficult to figure out how to cover a few spots and I think that will do the trick.
R Ranson, I've noticed similar patterns to the visits. Today though had been gray and drizzly and it just showed up an hour ago. One of my hens is good at alarm calling as soon as she spots it. They are locked up now. I have one of those indoor/outdoor backyard coops so they can be in for a few days.