On several occasions after a predator attack, I've found hiding chicks and older chickens in the most improbable places, and I never would have found them without being on foot and looking.
I found five missing six-week old chicks unharmed stuffed in a few inches of space behind plastic trash cans full of firewood on my front porch, a place none of my chickens ever go.
After another predator attack, I found a three-month old chicken stuffed into a three-inch crack between two bales of straw under a pine tree.
After hearing hysterical squawking outside by bedroom and looking out to see a big cloud of feathers settling after a hawk had dived at my young pullets, I found the victim afterward hiding in the coop, uninjured except for missing every single feather on her back.
The most dramatic predator incident occurred when two dogs attacked my flock while they were outside of the run. My two roosters disappeared as well as the two dogs. I got all of the hens into the run safely, and none were injured. But I assumed the roosters were carried off by the dogs.
I was heart broken that I'd lost my beautiful boys, but there they were the next morning waiting outside the run. The dogs had not injured them, but they both had extreme cases of frost bite from being exposed all night that had been down to 13F.
Yes, I've had a few casualties. I lost two hens to bobcats, and one to a hawk. I've had many bear attacks, but none of the chickens were lost. I now have hot wire wrapping around the runs and coops energized 24/7 by a solar fence charger. I bait the hot wire with peanut butter for bears, and canned mackerel for bobcats, and predators, after engaging with the baited hot wire, have learned to give my coops and runs a wide birth.