I'm so sorry
Its a terrible loss!
I fear that all the time, and I've come to the conclusion that our luck with hawks, owls and eagles has a lot to do with our suburban property. There are many, many ways for our chickens to duck and cover, and some areas where the hawks have a very hard time maneuvering to land.
One had managed to land close enough to walk over to our little brood of chicks, but the hawk was attacked by the broody hen (Silkie!). It tried, and tried to get away and finally just managed to crawl over the 3ft picket fence with our Silkie hen still attached to the back of its head.
At first we kept our chickens penned and covered, but that was nervewracking, the hawks would sit and stare at them and walk across the top of the netting terrorizing the chickens. Eventually we just got used to answering the "alarm" call and keep brooms by the door. Once on the ground, the poor hawks or cats or coons have to deal with the pack mentality of our flock, they group up and stalk it, all the while doing that loud "alarm" call. Its true, hawks don't seem to recognize humans at all, much less fear humans. But they keep their eye on the chickens until they get tired of waiting for a way to get to them. I guess our yard is just too much work. We live by a river, and I bet the fat ducks are far easier prey!
We still get hawk swoops, and hawk ground-walks, we even have a bald eagle hen who's landed on our rooftop, but the Good Lord keeps blessing us with freedom from loss yet another day.
I still think a herding dog would ADORE the job of keeping a flock of birds. It would count them, call them by name, watch the skies, oh happy happy dog life for a herding dog!