Usually feather eating seems to be related to not enough protein in the diet. However, feather plucking/picking is most often a behavioral manifestation of boredom and/or an inadequate amount of space for the number of hens you have. There's also the possibility that you could have a little of both going on. You might want to consider a higher protein feed or add in some high protein treats as well as re-evaluating how many hens you can house in your coop/run. Remember, minimums are just that, bare minimums, and unless your hens are getting a lot of free range time the minimum recommended amount of space is usually not really enough. Rehoming a few birds, adding more square footage to your run, and providing enrichment (such as a flock block, throwing some dry leaves or a pile of straw in the run for them to dig through, hanging suet feeders with treats such as fresh greens on the sides of the run, etc) or a combination of one or more of the three will probably help.