Went outside and heard some of my chickens raising a ruckus and found one of my hens a few feet away from the coop door. I picked her up and she was still breathing, but as I held her and tried to find any wounds, I realized she was dying and before I blinked she took her last breath. After I composed myself, I did a better examination of her and found this at her vent. I have never seen this before and have no idea what it might be.
