I am so sorry you had to experience a loss. It stinks, to say the least.
I had one loss to a hawk a few months back. I didn't see it(thankfully) but my husband did. The hawk was just sitting there happy as can be, and all that was left of the chicken was a pile of feathers and the skeleton.
I have read here that hawks tend to carry the chickens off and eat them elsewhere. In our case this was a full grown standard sized chicken, so to be carried off might have been difficult. But from what I have read, yes, it could have been a hawk. But there are other possibilities also- one being a dog.
Unless there is a witness, or some really good tracks, it may be impossible to figure out what killed your chicken. Whatever it is, it could come back, and I would act on the assumption that it would be back.