I'm sorry you haven't found themThere's no sign of either hen in our three acre yard. Not even a place where an "abduction" could have occurred, that I could find anyway. We are surrounded by woods, but I've searched the perimeter of the property back into the woods a bit and again found nothing.
Yesterday morning, I heard a hawk at the corner of our property in the woods a bit. I'd wager that if I found the nest, I'd probably find remains nearby. Sybil was taken at night, so I doubt a hawk got her, or do they hunt at night? But Anna was taken in broad daylight so my money there is on the nasty hawk.

I would think since you have found no traces, it was probably Fox or Coyote. An adult laying hen is much to large and heavy for a Hawk to carry off.