I've got two layers currently, a pair of 18-month-old Australorps. Until last weekend, they were both laying pretty consistently, about 3 eggs every four days. It's very apparent which eggs are from which hen - they are noticably different shades of brown, and one of them is longer and narrower than the other. Anyway, one of them has not laid since last Monday. She doesn't seem to have any health issues - close check revealed no mites or other pests, vent seems normal, she's not behaving any differently, eating well, drinking plenty, and since she's the bosslady, she gets the most of whatever fresh foods go in the enclosure. They're kept in a tractor with three pullets of about 20 weeks, and there's a very limited number of places she could hide eggs. I replace the litter in the henhouse every 3-4 days as needed, but I've stopped cleaning out the nesting boxes because the older girls kick all the straw out when it's new, and seem to prefer older, kinda dirty straw. Also, the little girls like to "play house" in one of the end nesting boxes, so the older ones have consistently used the middle one. Only twice have I found an egg outside of that box - once on the floor of the henhouse and once on the ground in the dustbath they scratched up. So...any ideas why she's stopped laying? I'm not sure what else to say as far as conditions; as far as I can tell, she's perfectly healthy, but I'm a novice, so I may be overlooking something blindingly obvious.