I have two coops in yards next to each other. In both coops the two year olds (Australorps and Buff Orpingtons) have basically totally stopped laying. One of the coops has year-old Rhode Island Reds, and they are laying just fine. I know from a long history with these breeds that they lay heavily for several years. I thought the problem was that I had turned off the winter lights too soon, but they've been on back on now for a couple months (14 hours). There was a mild mite/lice problem, which we treated using pyrethrins and diatomaceous earth (food grade) about a month ago [many of the hens have featherless, reddish "bottoms" which are improving since they got dipped]. Everyone is on the pellet feed, oyster shells, water, etc that we've used for years. Occasionally a hen will have some liquid poop, but for the most part the poop is solid. They all seem perky and eat plenty. What's going on???? Is there a situation when for whatever reason they get "turned off" and never lay again? I can't afford all the feed if I don't get any eggs. Also, I have 6 new pullets which I hope to introduce into one of the coops soon, but I'm not sure if I have a problem or not. Please advise.