I won't brood them in the house. Be careful with heat in your coop, though; every year we read about doop fires. Be sure the heat source is secured at least two ways, and if you have one of those metal hooded clamp on lights, the socket where the bulb goes should be ceramic, not plastic.
You'll pretty well be able to tell whether they are warm enough by their behavior. If they will be shipped to you, they need the most warmth (and attention) for the first few days after arrival, as shipping is hard on them. One approach is, set up your heat source before the birds arrive, and check the temp under it during the night when it's coldest. Of course the chicks will add a little body heat. Be sure there is no draft on them, and that they have plenty of straw or whatever to cuddle into. I would check on them during the night for the first night or two, at least.
