Also, make sure to only put the lamp at one end of the box so they can get out from under it if they get too hot. They can die from being too hot as well as too cold. 100 was a little too hot for my chicks, they would stay far away from the light, they seemed to prefer 90-95. You can tell if they're hot or cold by their behavior, if they constantly huddle together while standing up, right under the light, they're cold, and if they always stay far away from the light or if they pant, they're hot. And be sure to follow chicks4kids' and chickenvirgin's advice about reducing the temperature as they age. The easiest way to adjust temperature is to raise or lower the light. I always keep a thermometer or two in their box to monitor temps.
A regular light bulb for heat is fine, but a red bulb may help them sleep better at night. Just get the same wattage you're using now, but a red bulb. You can get the red bulbs at pet stores in the reptile section. Yes, chicks at this age do sleep a lot. As long as they're running around active, eating, drinking and pooping normal when they're awake, they are ok.
Good luck with your new babies and post PICS!