What was the most likley preditor?

One of our hens was killed last week while free ranging. We assume it was a hawk as they are always flying around out here. We have been lucky up until now. I found her in the field mostly eaten and feathers everywhere. I was wondering what preditor would most likley leave it in the field. it happened sometime between 7-3 but we think it was that morning because the feathers were wet and it had been raining that morning. Since this happend i have left them in their run. As of right now we are quarentiening new birds so we are having to leave these girls in their own run too until the quarentine is over but when i do let them out what would be the best time of day to avoid hawks? I heard they mostly hunt in the early morning and evening but i dont know if letting them out mid day would help to keep the hawks from getting them or not.