Chicks should stay under a heat lamp for about 4-6 weeks, until they have enough feathers to keep them warm. During the winter months, keep a heat lamp in your chicken coop, especially if the temperature gets below freezing. When there are days with less light, the chickens will stop laying eggs. We have found that keeping a heat lamp or light on during those shorter days helps our hens to lay more consistently. We like to keep the heat lamp on a timer, so it isn't on during the daytime hours when they don't need a light.