I had all my hens stop laying completely one winter after a hard moult. Never had happened before. I found some info on it I think on the internet and put up lights on timers, got some Super Layer Pellets 22% protien to mix with thier scratch, and started putting apple cider vinegar in thier water. In two weeks they were laying again. Now in the winter, I do that but I dont use the vinegar anymore. Once it warms up, I put them back on 16% layer pellets. I get the Dumor brand. They seem to like it.