We have been having the same problem since last spring. We have a RIR that someone had been breaking off her feathers, then plucking them out all together, near the base of her tail and up onto her back. We applied pick-no-more, blue kote, with no success. Then this summer a fox got the hen that we thought was picking her feathers. Her feathers began to grow back. Now, once again we are having a feather picking issue. This time it involves the same hen as before along with another hen. Both "pickees" are RIR's. We have no idea who the "picker" is. We have 14 hens. We have seen some disruption in their normal behavior that I had attested to losing Ms. bossy pants that met her end this summer. I assume that it is to re-establish the pecking order.
The hen that is getting picked now is almost completely bald underneath, on her belly, all along her keel bone and halfway up to the underside of her wings. She also has a bare area about the size of half a dollar bill on her back to her tail. I made her a saddle out of polar fleece and tent fabric for water repellency to try to cover this area so that the picker couldn't get to her feathers. This weekend she ended up getting it tangled up in wild rose thorns and my husband had to get a pair of pruners to cut her out of the tangle of rose canes. So I'm not sure that the saddle is the best way to go. I don't know how to figure who, among the remaining 12 hens is pulling her and the other hen's feathers out. It is extremely frustrating. I fear for the poor girl missing most of her feathers on her underside, as the temperature is supposed to drop to the teens during the nights this week with one day down to zero.
We have been feeding layer ration and supplementing with cat food to see if it is a protein deficiency. It doesn't seem to be making much of a difference so far. How soon should we see the behavior cease, if it is only protein missing in the diet, versus just bad behavior?