We have 3+ week old chicks in their coop w/ a heat lamp set to 80 degrees and plan on moving this down by 5 degrees per week. However, this will leave them in periods of darkness as the temperature fluctuates. We have a regular light set up on a timer for early evening. We have a window in the coop but no direct light gets in as the run has a roof over it. During the day there may be long periods of no light in the coop and the small filtered daylight only...is this ok?