Don't assume there's no way in to the coop. Several years ago, someone here was losing a chicken every night. Occasionally the dead and mangled chicken was left inside the coop. The doors were all closed and locked. The chicken keeper was convinced the other chickens were the ones killing. We urged them to install a game cam.
What the camera caught was a raccoon coming into the coop from a crevice in a far rear corner that they weren't even aware of. Somehow, the raccoon was able to compress its body to fit through the very narrow crack. Once they sealed up the crack, no more dead chickens.
What the camera caught was a raccoon coming into the coop from a crevice in a far rear corner that they weren't even aware of. Somehow, the raccoon was able to compress its body to fit through the very narrow crack. Once they sealed up the crack, no more dead chickens.