I hatch lots and lots of chicks every week in my dining room ( last week 76) and after 1 week the little darlings go outside in plastic brooder tubs with a wire lid a heat lamp sits on that has a regular 65 wt bulb in it. During especially cold nights, because I hatch all year, I cover half of the exposed areas of the wire with a hand towel.
After about two weeks I move them to an enclosed wooded box brooder that is roughly 4X4 with 1 or two heat lamps depending on how many babies are in there at a time. Same light bulbs as above. I never use brooder bulbs as they are two hot.
After about two more weeks the chicks go into a 6X8 shed with wooden walls and a hardware cloth wire door. I leave 3 heat lamps with regular bulbs hanging in various areas out of drafts incase the babies feel the need to sit under one. I also have a roost in the shed. When the babies start roosting, I move them to a big bird pen with other babies and no lights to continue growing untill they are sold or go into the breeding pens.
This system works great for me and I don't have to worry about babies getting too cold.
Lanae