Looks like feather picking. Have you observed your flock to see if you see it happening? Generally caused by crowding and boredom or a protein deficiency.
Interesting, davidsilber has the same pictures, similar issue. Mites/lice? Feed? Crowding?
How much area & how many chickens?
davidsilber says feeding layer from TSC, try changing to Flock Raiser (higher protein) with Oyster Shells in a separate container for the hens.
Mites/Lice dust with Poultry Dust, check the coop/run & treat with permethrin spray.
Hi can I help me some one any one I.ask on here is rude to when iam trying to get help for chicken hen. When iam nice person. I need help with a hen I will answer qutions will try