I get it, but try not to let others bother you. It isn't personal, and anyone who has had animals for anytime will assure you we all have had set-backs and disappointments. Bertha and Percy are not your fault, so accept it for what it is, Not Your Fault. I am faced with a culling too, and it...
People will continue to respond, until this post gets buried under newer posts. No one is going to read all 60+ posts, so you will continue to get repeating advice. Just ignore, it will get buried and forgotten eventually.
Is Bertha behaving?
Sometimes you just get a bad hen. Killing is really the kindest option. I know it seems harsh, but chickens are meant to live in flocks, not caged away alone.
I wouldn't cover her vent. That would be messy and may lead to complications. I was thinking of just trying to protect the tail, a shirt that remains open but just before her vent.
I know you are feeding them well but maybe try to increase their protein. I feed mine beef liver over the winter. Otherwise I read a good tip to stop picking. Someone suggested you buy a couple baby shirts and cut holes in it for the birds wings.
If you could get one long enough to cover...