As mentioned in my quote, we don't house chickens in the human house. Ever. A safe enclosure, a heat source with room to escape the heat, and food/water and they'll be fine. If you're in FL as your username suggests, they won't need much heat or for long. Careful not to roast them.
We're a "no chickens in the house" family. They live in an outdoor brooder/grow out coop from day 1 (that translates to 3 days old because I don't hatch and the guy who does hatches mid-week, sells Saturday). It really is easier to transition them to unheated outdoor temps when they are...
They're telling you they are too warm. If they have feathers on necks/heads/backs, they are ready to shut off the heat altogether. As for inside/outside, the answer is day 1 with a heat lamp. Chicks never "need" to live in a human dwelling. But I think you meant when is it warm enough to be...