Sorry to hear that, but lesson learned, you will never forget to shup up your birds at night ever again.
We had a fox left three headless runner ducks in the run. Worst thing was they dont kill to eat, just for fun from the looks of it.
And my farmer next door actually feeds the fox. Fortunately, my fox terrier and Jack Russell have had a couple of run-ins when mr Fox has come into the garden at night, and Now we have Colin the sheep on patrol, the fox leaves us alone. See the sheep, hear the dog, thinks to himself "not worth it"