I am soo sorry for your loss, and I can totally relate to the shock of coming home to a slaughter that isnt your fault. My previous flock was totally wiped out by neighborhood dogs one day while I was gone to town to finalize my divorce. I come home with my sad children, in freezing weather, to find the first carcass in the driveway. My dogs were still in their kennels and were barking frantically at the neighbors dogs who were still in my yard. All of my chickens were shredded all over the yard, not eaten, just killed. I couldnt get to a gun in time to take care of the dogs, but when I spoke to the neighbor, I still had enough of the "crazy eye" going on, that he promised me that the dogs were gone, and they were, that afternoon.
My entire yard 1.5 acres is fenced in chainlink and field fence, with hot wire that has a power source set for 10 miles with 3 grounds. I have to have warning signs up for humans, and my own dogs have only touched it once, and they all now avoid it like the plague. My chickens are in a 30x30 coop that has chicken wire, electric fencing and a 2 ft no mans land that has rock to keep anything from digging in, so needless to say, the only loss I have had was my tiny suffolk hen that stuck her head through the fence,(after that I added and interior buffer that keeps the chicks off the fence as well), and I belled my dogs, so that the chickens can hear them coming, and the birddog has a 6 ft chain that she drags as well. It may seem like overkill, but after dealing with my traumatized kids, and my own heartbreak over the loss of my first flock, I decided to take no risks. Hotwire fencing is the way to go, it really makes an impact and it doesnt cost that much to operate.
Good luck to you, and again, sorry for your loss.