Try putting some boredom busters in first. Then try the Pinless Peepers. If you don't want to do the Pinless Peepers, put her in "jail" for two weeks to a whole month. That'll take her out of habit and possibly pecking order. If you do Pinless Peepers, do them for two weeks. Not longer, because they can cause irritation and nasal issues if left on longer. Also, an experiment I'm going to be doing soon, is doing an anti-capitalism spray on the birds. (I'm currently dealing with a whole flock plucking issue.)
Issues like this bullying, along with plucking, can come from the boring winter months. Honestly, Spring is when my birds looks their worst due to all the bad habits the flocks picked up during the winter. (This is including my crazy broody twice, soon to be third time broody, beard plucker, mounting my hens to the point that they look like a rooster's favorite. And yes, I'm looking for a rooster...)