3 less chickens

Lost 2 brown ones and a mixed (acorn squash, butternut's favorite) to predation. I felt something was up and couldn't find Butternut around the house. I went down to the creek and found a lot of feathers and a still warm chicken carcass with no head. I was worried for Butternut, our rooster, but found him on a tall big cedar stump overlooking the scene. He was sure happy to see me and flew down feeling safe and running back to his flock telling them all about what happened. I would like to understand chickens and hear his story. We set up trail cams but didn't get any clues who took our chickens. Coyote, bobcat, raccoons are all in our backyard and possibilities. There is only one witness. Only butternut knows...