If I lived somewhere with a nicer climate, I'd have them outside from the start. But, not even I can really be comfortable outside in early spring here. It's too wet and windy.
I don't have a picture of our brooder...but this year we're only raising 3-4 chicks. They're kept in the cellar until they're fully feathered and big enough to hold their own with the adult birds in the coop (after slow intros, of course).
I adjust the heat lamp based on their behavior. I...