Sad update.
Willow was euthanized yesterday. She had a 6 week break from her condition, but it hadn't responded to vitamin treatment over the last 8 weeks.
Her brooder-mates were very tolerant of her up until point-of-lay. Willow became a target for birds looking to increase their standing, and what would normally be a pecking order dispute, turned into full-on bullying and chasing. They clearly did not want her in the flock.
We attempted to partition her next to the flock for safety, but Willow became so distressed over 3 days that she barely ate or drank. Her backing up became almost constant. She spent the days pacing the partition wall (even with the other birds right next to it) and nights crying until lights out. I did not believe she could handle a rehoming in this state, and a new flock would be unlikely to accept such a weak bird. In addition, I can't really say how uncomfortable these backing up episodes are for her. But to be so stressed that you're unable to eat, drink, move forward, evade bullies, etc...
She was dealt such an unfair hand. I'm absolutely gutted. So please let this be a caution to anyone that has a chick like Willow. Her friends may accept her while they're young, but that will almost certainly change after 12+ weeks. Be prepared for the worst if you cannot get your bird healed.
I love you, Willow. And I'm so, so sorry.
You did everything you could for her, and for longer than many other people might have. You have her a comfortable life while she was here. 
