You have some feather pickers. You can increase their protein intake to try to combat this, but they won't get the feathers back until you figure out which ones are doing the picking. This is a nasty behavior that rapidly becomes ingrained and is nearly impossible to combat if you don't act quickly.
-Increase their protein intake
-Allow plenty of space for them to roam and avoid each other if necessary
-Provide distractions and places to hide in and around the coop and run
-Provide plenty of roosting space; spread the roosts out so they can't pick at each other while roosting
-There are some products on the market applied topically to make the birds taste bad- Hot Pick/No Pick, pine tar, Vicks VapoRub
-There is a very effective product called pinless peepers which is a little chicken head gear that blocks the direct line of sight; not all birds can wear these and they should not be used on free-range birds
I hope this helps.