My 9mo Welsomer hen has recently started first pulling her feathers and then pecking her rear under her vent. It was a bloody mess. I brought her in, washed her butt several times a day, used the rinse off antiseptic, hen healer, neosporin, made diapers from fabric like upside down aprons with a pad added, fed excellent food, blueberries, etc. But a few days ago it got so infected and smelled horrible, dead flesh and has eaten away a chunk under her vent like something took a big bite out of her. Her comb barely has color and even her eyes are pale. She's ripped her diaper off 2x today to get to her butt to peck til it's bloody and my bathroom is covered. I don't know what to do. Should I just put her down or is there a chance for her? Her poor butt will never be normal looking again so much of it is gone, just her vent left. Should I or not? I'm exhausted and I hate putting her through this if she doesn't recover. Is this gangrene? Help, please!