My chick are 4 weeks, I am wondering whether should be turning off the light off. I am raising them in very large igloo in me unheated garage outside gets down to 30 degrees, that to cold to have then outside.
Welcome to BYC. Glad you decided to join our flock. I would start weaning them off the heat lamp when they are fully feathered (around 6-7 weeks). Just make sure that their coop is draft free, dry, and well ventilated so that moisture does not build up inside. Feathers are wonderful insulators and moisture is a much greater danger than cold. Please feel free to ask any questions you may have. We are here to help in any way we can. Cheers.
I put a thermometer in the coop and would turn off the heat when it was over 60 degrees outside at that age and turn it on again when they huddled together and looked cold.
The next step was to put a lower wattage red heat bulb in the coop. Now I have a 90 degree bulb and I turn it on when it gets below 40 degrees for my 12 week old crew.
They let you know when they are cold!