Raising Chicks Without a Heat Lamp(Or a Broody)?

[Lorije1]

I have my chicks (between 1-2 weeks old, maybe?) in a tote bin in my extra bathroom. I stopped putting the light on them because they were always sleeping at the other end. Now they sleep loosely gathered together, not piled up. It is in the 70's in the room I would say. As soon as I get my chicken house finished up with the hardware cloth, etc they are headed outdoors (upper 70's during the day, upper 50's at night).