The fox that got ours was on a killing spree.

We heard the chickens cackling at 11:00 PM and looked out the window.
I saw a fox entering the coop and ran out the door to scare it off. Two chickens were dead in different parts of the yard, and one was wandering around battered (but not fried).
I put the stray chicken back in the coop, locked the coop door and went back inside.
As soon as I got inside, the fox was back at the coop, looking for a way in.
I then watched the fox through a magnified optical device, when suddenly there was a loud noise and a flash. The fox must have gotten scared, because it fainted right there.
The next day, I went to check on the chickens, and the fox was still lying there - must have been more scared than I thought - possible heart attack.
I'm guessing the bastard was just going to kill them all.