I have a menagerie of breeds and ages- Aussies, Easter Eggers, RIR, BR, BSL, RSL, and mutts ranging in age from 9 months to two years. There are 27 hens/pullets. About a month ago, egg production bottomed out. I had been free-ranging with only minimal feed in the evening, so my first thought was that they had moved nests into the brush. I started penning everyone up at night and turning them out mid-day. No improvement in egglaying...so I thought maybe they weren't get sufficient nutrition with the free-ranging. I started back on free-access to 16% layer pellets. No affect. I've examined every nook and corner of the coop to verify there are no predator holes. I've dewormed and added light. So now I have 27 hens penned up 24/7 with free access to water and feed, and a heat lamp on them 24/7. I haven't had a single egg in three weeks and no one's even going to the nest boxes. Each box has a nest egg in it. No change to location or nesting material. No one's molting.... Any ideas?