My money is on a mink or weasel. I have first-hand experience with minks -- and I hadn't had any problems until one night when I did. The remains sound just like what I found. One hen managed to fly up onto the highest roost and survived. Maybe she wouldn't have if I hadn't been alerted to the massacre by my dog.
I also thought my coop/run was pretty safe. I am now a big promoter of hardware cloth. I am very sorry for your losses and the poor lone, traumatized survivor.
I also thought my coop/run was pretty safe. I am now a big promoter of hardware cloth. I am very sorry for your losses and the poor lone, traumatized survivor.