5 of our 11 hens are losing the feathers on their backs just above the tail feathers. Our RIR, Jersey Black Giant, Austra. and a buff. The white leghorns, barred rocks and the delaware are fine. We get 10 -11 eggs a day so it definately isn't a molt. We're thinking either mites, or pecking by the "white" chickens or maybe the heat lamp is too close to them. They are all almost a year old in April. Do we need to take one to the vet? Is there something we can do ourselves? The coop run has been VERY wet this winter and rarely gets a chance to dry out. Poor gals don't get a chance to give themselves dust baths every day.