So sorry for your loss...a cooper's hawk attacked mine twice while I was sitting 20 feet away. That pop up canopy with netting is how I keep the girls safe now. Big Lots has them for $130. Easy to move around the yard.
My chickens were attacked twice in two days, but thankfully I was there to chase the hawk away. I now have a screened canopy to protect my girls while in the yard. I feel bad they are limited to an 11 foot by 11 foot area when outside their run, but they are safe (I hope).