So I am very puzzled and have been for some time. My 8 RIR hens have not been laying for about 12 weeks now. They were laying fine until the colder weather hit. I started their heater and they have a good light source but they are not laying. They just finished molting 4 weeks ago and still haven't started laying again. I need help to get egg production back, what is wrong and how do i fix this problem????