Have you dusted her for mites? If not, as a precaution I would. Not sure where you live, but typically, molt happens in the Fall when the nights become cooler and days become shorter--signaling colder days ahead/time to build new feathers for winter.
She's at the bottom of the peck order...
Poor little sweet hen. Any rooster in the flock? I'm wondering if she got picked on, lost some feathers, and now, while she's trying to grow them back--the hens keep picking out the new feather growth.