My oldest hen has stopped laying and appears to be losing her feathers around her neck and vent. I do have two roosters but only one is dominant and neither pays much attention to the older hens, he like the young ones his age. Could she be moulting? I know that there was a post dealing with this but I could not find it. It seems kinda late in the year for her to be moulting but I can't see any signs of mites or aggression that could be causing this....suggestions?