I've had Cooper's hawks, GHO, and Red tails enter my pigeon lofts through unsecured bobs. They have not been gracious enough to only visit. The larger birds killed multiple pigeons, and the Cooper's killed and ate one. After being released, the GHO returned nightly trying to find a way into the loft. Needless to say bobs are secured each night even if my best pigeon has not returned!
Oh, my. The question that nags at me is - how on earth did he get into your coop?!
I honestly would probably have alerted the entire freakin' neighborhood if I opened the coop and saw those EYES staring back at me. Chicken eyes look silly at all times - that thing's eyes would scare anyone half to death at night.
What a cool thing. I am glad that your chickens are okay. But it is wonderful that you got the opportunity to see the hawk up close and personal. It will be a great homeschooling project to learn more about Copper hawks.