I have a RIR hen that's hasn't laid for over a week (the 17th was the last time), and before that, she'd been laying quite regularily. It doesn't appear to the usual causes: 1. Lighting - I've been giving all the hens extra lighting for at least a month, now. 2. Cold - it's getting chilly at night, but I thought RIR hens laid all winter long. It's not really that cold, yet to be affecting her when all the pullets are laying just fine. 3. Stress - Nothing that I know of has happened that could have stressed her out, and there haven't been any recent changes to their "home". 4. Molting - She's has beautiful feathers, and doesn't appear to have any falling out 5. Food & Water - She's been getting plenty of both 6. Age - I don't know her exact age, as I got her from a friend in April, when she was about 1 year old. So, she's still egg-laying age. 7. She appears healthy, but I haven't closely examined her, since she's the only one that won't let me get within 4 feet of her.