My four pullets keep sneaking up behind each other and plucking feathers out of each others buts and eating them. Their food is supposed to be high in protein so I don't know why they're doing this.
If it is a protein issue, increase protein, mealworms, scrambled eggs, meat. If boredom is the issue, more space and/or something to occupy them, like a treat ball with broccoli or lettuce. If they are near POL you could put a Flock Block in for them to peck at, it has supplements and treats in it(also calcium, that's why they need to be at least 16 weeks)