When the days started getting shorter, I only had one of my pullets laying. They were all 20 weeks old when one started laying. She was an egg a day for a week then took a day off. After two weeks, on thinking it over I decided to go ahead and put a light in their coop because I wanted them all to at least get started before winter came and the days were really short. We have it on a timer set to come on at 3:30 a.m. and it goes off at 7:30 a.m. Then it comes on again from 5:30 to 6:30 p.m. Last week we got 3-5 eggs a day. Yesterday and today, we got 6. The girls don't seem to mind that it's gotten chilly. It's funny though, when the light comes on in the coop in the evening, they go inside even though it is just dusk. They really like that light!