How to stop feather pecking!?

[RootedTogetherHomestead]

So, one of our girls has feathers missing on her vent area (Butterfly). We watched and saw the culprit and what was happening. Sunshine (the culprit) pecks at Butterfly's butt feathers whenever she is dustbathing or preening herself. I think Sunshine thinks she is helping? as there is no blood drawn and Butterfly doesn't seem to mind. Butterfly is one of the top girls and has no problem putting Sunshine in her place (seen it before). How do we stop this? We got 2 flock blocks, cabbage hanging, we let them out whenever we can (a lot of predators in our area), and give them scratch grains with meal worms often. They have 12sq ft each in the runner. We have clutter in the coop. Is there a safe spray or deterrent we can put on Butterfly to prevent Sunshine from doing this? TIA!

Edit: They have 20% protein Kalmbach feed and OS, and grit.

 

[Frontyard Chicken Owner]

I had a problem like this. They make plastic "blinders" that clip onto a chickens face, called pinless peepers. I used them and they worked well ,the block a chickens forward sight but they still see everything else well. Try giving them scrambled eggs for extra protein as well