So we got a group of four hens and a rooster in september and they laid fine for a few days. Were even laying in the car before we got them home. We bought a premix food with oyster shell and started them on that. After about a week of 3-4 eggs a day. NOTHING. it just stopped. They have an enclosed pen and can't get out, we clipped their wings to be sure. They have an enclosed coop and are closed in at night. It's been cold but it was just as cold and dark during the day when we got them. A few weeks ago we added 4 cuckoo maran hens and one maran rooster and got 3 eggs the next day. Then they stopped. The first set of chickens were swollen and stopped up, we switched to a nutrena layer feed and they swelling went down and went away all together. They seem to be eating great very active and lively, no unusual or off poo. Wattles and combs are all bright and pretty. They seem perfectly healthy and so far no signs of molting. So what's up? I'm confused. Any suggestions? I'm getting about 30 new chickens here in the next few weeks (day old chicks from mcmurray) and I want to make sure everything is okay before hand. Help help help!