I have 8 chicks almost 5 weeks old. They are kept inside and with the warmer temps I started just using a 75 watt bulb but only at night. They are kept in a finished basement so it is a bit darker down there even with all the blinds open. The bulb was on a timer and I began to notice that the chicks were super active at night with the light and were sleeping and roosting during the day without the light. I think the bulb was much brighter than the regular room light during the day and they started to mix up day and night! The past few days, I stopped using the light all together and they are now up and active during daylight and sleeping at night. I still have a small night light just for some ambient light. Is it possible that they could have confused day and night with the light on a timer?? They seem fine without the heat at night and are feathered nicely. Do they still need the heat at night??