Please keep us informed on her progress. Fingers crossed for both of you. She was strong enough to return to where she felt safe. Let's hope it was soon enough. Looked for a fingers crossed emogie,, or what ever there called, but couldn't find one. So fingers crossed.
Do you have a game camera? That's the easiest way to find out what your dealing with besides actually seeing the culprit.
Unfortunately, what ever it was will be back.
Coon. That are known to eat the head off the chicken. The missing one sounds like fox, but a coon will drag a bird off. The nest being raided sounds like a coon also, but could be anything from a snake to a coyote..