Infrared Heat Bulbs (white light) are used for chicks whilst they are still young and in their first few weeks of life. Once chicks reach approximately 3-4 weeks (guide only), the bulb should be changed to the Infrared. Light Bulb as they supply less heat (required at this stage in their life). Infrared lamps (red light as opposed to white light) do not interrupt chicks sleeping. Red lamps also help reduce chickens pecking each other.