Actually, many folks brood right in their barn or coop, if they have electricity. But your question is more about two things. Containing them within a small area so as to not get into harm's way. Second, their warmth requirement.
Since summer is upon us in North America, the heat requirement in many places, will be minimal. It will be quite easy to maintain all the heat they need with low wattage lamps. You can likely ween them off any added daytime heat quite quickly, within 3 weeks, as ambient temps are so high this time of year.
At 5 weeks, the chicks are feathered out and won't likely need any night time warmth anymore either. Enjoy your new chicks.