How is her healing progressing?
I wonder if you put a saddle apron on her back if that would deter the others from pecking on her?
I also wonder if you can let Cheeks have some limited free time roaming outside with you present when all the other chickens are confined in the run? This would give her some fresh air and sunshine, ability to roam about and peck for bugs and she and the others would see each other but they wouldn't be able to access her. It might lift her spirits and outside time to help with healing. You mentioned you didn't have a crate that fits in the run so I was just trying to think of a way to allow for some natural safe chicken activity.
