OK, I've got a flock of 10 hens, 8 of which haven't laid for about six months. They aren't molting. They don't seem sick, although some are a bit skinny. They are locked away at night -- no predators scare them. They aren't very old (between 1 and 3 years, and they used to lay LOTS) I give them oyster shell and a high quality laying mash and not too many scraps or too much corn They've got a nice big yard and four nesting boxes. We've got a rooster and they don't like getting mated that much, but he's been around for several years, and they always used to lay I've: treated them with Sulmet (about four months ago) treated them with Piperazine-17 (about four months ago) treated them and the yard with diatomaceous earth Why oh why oh why aren't they laying!?!?!?!?