We just got a Polish pullet over it completely.
Our experience was that she worsened dramatically when she was stressed, including when we held her or tried to "help" her. If we left her alone after a few minutes she'd be able to uncurl enough to eat and drink. She could still see well and aim her head if she was relaxed enough. Helping actually DIDN'T help.
There were several weeks where she could not move forward at all. Only backward. We kept her in a dog ex-pen during that time and she'd maneuver backwards, often falling over and flapping, until she was facing whatever she wanted to face, then work on getting her neck down to pick it up. It was pitiful and awful to watch, but believe it or not she didn't seem distressed and she didn't lose weight or condition.
She got a capsule of salmon oil and half a capsule of super-stress B complex every day or every other day, depending on how she was doing.
After a month we saw that she could move forward. From that point it was only a few days until she was holding her head normally most of the time. She would still flip it back into the twisted position if she heard a loud noise or was scared for some other reason. But then even that went away pretty quickly, and yesterday she moved back out with the flock.
I told myself the whole time that if she stopped eating or drinking, she was done for. But, amazingly, even at her worst she could eat and drink.