I'm very new to raising chickens. I have/had just two hens. I check on them every day and give them food and change their water. They both hadent laid eggs in aabout 2 days. But sometimes they skip a day or 2. I went into the coup today and both of my hens were dead. I live in upstate New york I'm not sure if the cold had something to do with it but they have survived through much colder nights,the water had not froze over which happens on the worst nights. My coop is well insulated and there's always a heat lamp on. Any thoughts on the cause.