I have chicks that are 6,7, and 8 weeks today. I have had them under a red bulb. I read somewhere to start turning off the light for a little bit each night to get them acclimated to darkness, so I just pictched them into total darkness a few minutes ago and so far so good. How long should I leave the light off. They are still in the house and feathered out enough to not really need heat anymore. Should I leave the light off from now on. Thanks