My girls are 3-4 weeks old now and are feathering out. I have them in a 50 gallon tub and in my den out back. No heat in the den but fully insulated dwelling. My question is can I turn off the heat lamp? I have been raising the height of the lamp each week and the girls seem fine. Can I remove the heat source yet? They are growing fine. At what age should I move them to the outside coop? We have our temps getting down to the 40's-50's at night and the days 60-70's. I don't have a heat source hooked up in the coop. Anyways, the girls seem like they will soon outgrow their current quarters and need to think about the move. Any thoughts?