A bulb would help but DO NOT put a heat lamp/heat bulb in!! Just one that makes regular light! If you didn't already know, it's dangerous to put heat lamps In coops because once you turn it off there's a high chance they will get sick or possibly die. Just as a heads up for winter, don't put a heat lamp in unless you have below -20F temperatures.Okay what if I add a bulb or something to increase the egg production and yes it is winter in here !