The Case of the Missing Chickens

On Monday, April 8, something strange happened. I went out to open the door of the chicken coop to let the chickens out, just like I do every morning. But when I got there, I found the door already open. Maybe I had forgotten to shut it the previous evening. That would be bad, as leaving the door wide open leaves the chickens vulnerable to foxes, raccoons, possums, etc.  Upon looking inside, I saw that something had apparently taken advantage of that.
All 32 chickens were gone, and there were black feathers everywhere. But only a few of our chickens were black, so this doesn't make sense. Plus, how could one animal eat 32 chickens? We don't have coyotes in our neighborhood, so none of the animals here hunt in packs. We searched the whole yard, but didn't find any other evidence.

The chicken coop.

A few days later, my dad was working in the garden and found a hole with feathers in it. These feathers were barred black and white; presumably from a Domonique chicken, which we had several of. It looked as if something, maybe a fox, had buried a chicken there and come back for it later. Not long after, we found more evidence that seemed to point to a fox.
The fence in the back corner of the chickens' yard was bent, and a hole was dug under it. It certainly looked like a fox had done it.

We've come up with a theory that at least explains why there are only black feathers in the chicken coop: The three full-grown Black Australorp hens were harder for the predator to grab hold of and struggled, explaining all the feathers. But the little chickens, who were only about 8 weeks old, were much easier to kill and carry out of the coop.

That's all we could come up with. Our friend suggested that the Chicken Hawk took them, but I'm pretty sure that's not what happened. If you have an idea, share it, please!