I have seven 15 month old hens. Six Buff orpingtons, one Australorp. All born in march 2012. At 19 weeks, they started laying. They've layed every week since that 19 week mark. I kept a light on through the winter till 8:30 pm so they'd keep laying. Only 2 of them have gone through a molt. That molt was in the spring, which was unusual. Last week we went on vacation. My housesitter said that they didn't lay at all. Now that we're back, they still won't lay. No sign of sickness. Healthy appetite's. Drinking water. Scratchin and cluckin as usual. But, no eggs. One thing that happen last week though, one of our girls was battling cancer. She lost her fight. They where all sisters. Could they be in mourning? Sounds silly,I know. But, I'm searching for an answer. Can anyone offer any advice?