No her run is huge but her coops are secure, homemade built on concrete. She has had several coops and runs in bear country over the years. Her idea is that something like a rat tunneled under somewhere
So i am keeping my mom posted on this because she is surrounded by so many predators and she says she doubts the scared to death theory too because she has watched a bear eat a rooster while a hen sat right next to it and silently watched.
If the bear did scare them to death (which I doubt because my mother lives in bear country and has had several raid her coops and never a chicken scared to death) that doesn't explain the missing feathers.
If it was raining during the attack something could have gotten in by diggin under thr run, killed them (are their necks broken?) and gotten back out through the mud which would look undisturbed by morning. I don't know what would do that though and not eat them...