I'm bumping this topic too. Seven of my girls look like the photos. The other 15 are fine. I've heard that we can dip our chickens in a sevin solution and allow them to dry in the sun. Does anyone do this and if so...what concentration of sevin to water? Do you use the 10% Sevin or the 5% Sevin? I've removed the compost layer in the floor of the hen house. Hosed down the tin walls with a vinegar spray and dusted the clay floor with sevin. I've sterilized the metal 10 room nest box with hot bleach water and dried it in the sun. Then when it was re-hung, mixed sevin and wood shavings in each box under a layer of clean hay. The water containers and oyster shell dispenser sit on cinder blocks. We use a hanging pellet feeder hung back high from the ceiling. It is filled with layer pellets. My girls have been treated with probiotics, pine tar, and sevin dust. Also, I use heat lamps hung over the roost to keep my girls warm in the winter. Could heat lamps cause the hens to loose feathers?