Added to the takeaway!I woud not get rid of the lamp, just the heat bulb. Replace it with a 40 watt or even a 25 if you can find them and it can be a great tool for getting them to go inside when it gets dark. They will naturally be drawn to the light as they are accustomed to it and it comforts them.
you can turn it off once they are inside and settled for the night.
You have beautiful chicks and have done a great job with there coop and box!