chickens usually molt head, neck, back, breast, stern, thighs, wings, then tail, and grow them back in the same order. some grow feathers in in less time than others. some chickens look only slightly scruffy whereas others go almost bald!. molting in addition to rooster activity could lead to bare backs. chickens also like to pick the iron and protien rich pin-feathers growing in so they may be picking each others backs. if feather picking seems to be a problem there are several anti-pick products availabe. a light coat of blu-kote would work too but it will turn your chickens purple!
