I had noticed that my broody hatched chicks were never under her during the day. We've had temps ranging from the high 50s to near 90 and they're out scratching around in all kinds of weather, nasty and nice. About the only time they actually are under her is at night. At 2 weeks old they started roosting with the big birds, which is saying something because my roosts are about 8 feet high. So- I decided to try to raise my hatchery chicks in a more "natural" way. I put them in an outside hutch at 2.5 weeks. They have a heat lamp with a 60 watt bulb to simulate their broody. During the day, I turn the lamp off. Then I turn it back on at night, just as my broody is doing with her chicks (they hatched 2 days earlier than my hatchery chicks). The hatchery chicks are doing fabulous outside. They are 4 weeks old today and are turning into beautiful little birds. So, I guess what I'm trying to say is, they will need some heat. However, chicks are alot stronger than us humans give them credit for. My chicks that are with my broody scratch around in the pouring rain all day, and yes they do need mama to keep them warm at night. They are some tough little suckers, and this may be a great alternative for you instead of brooding them in your house. I think the only thing I would have done differently was I would have moved the hatchery chicks outside earlier. Good luck!