Personally I don't use a light in my coop, I prefer to let nature run it's course. Many do add supplemental light to increase egg production and there are numerous thread discussions on the subject under egg laying/behavior forum. I would suggest you search those for the question and read thru those before you make an investment in this plan. If you do decide to pursue it pay attention to exactly how and when to add the light. And then, if this is the plan, post your question there for more opines and specific information.