I'm so sorry. She does look pitiful. Are you certain that she's doing this to herself? What do you feed them, including treats? Whenever they're like this, they tend to peck at themselves, but I believe most times, they're itchy and reacting to that instead of plucking themselves. I'm sure it's not unheard of but I don't know anything about hens plucking themselves. It takes a lot of watching to see if she's actually plucking her own feathers out or just regular preening. Her flock could be plucking her, which is seen on BYC seldomly. This is usually due to the flock not having enough space, boredom or feeding issues (not getting enough protein). How many birds do you have? How big is your coop, minus the nesting boxes? I'll tag some members that will be more helpful
@3KillerBs @aart @LaFleche