I don't have a photo of it but the underside appears to be normal. It had the same color as the other foot. I don't see any obvious puncture wounds where bacteria could have entered. I don't see any visible bite marks.
My vet recommended waiting a few days to see if it worsens. I'm a pretty visual person & notice even the smallest details that others miss. I didn't notice this until just a couple days ago. This particular hen is the runt of the bunch so I really baby her. I'm always picking her up & holding her.