Where are you keeping their brooder? If its inside, and they were mine, I would just turn off the heat lamp at night. 20 2 week old chicks should be able to huddle together and keep warm just fine. I decided to use a red bulb for brooding this time (I've always used regular bulbs, left on 24/7, with no issues). My brooder is outside, and its cold out there, so I didn't think my normal 60 watt bulb was going to cut it. I've noticed, with the red bulb, they aren't really running around at night like they did with the regular bulb. Maybe you could try a dark colored bulb? They make them in blue and purple. I would think they'd still put out enough heat to keep the chicks happy, but leave it dark enough for them to sleep. And they're probably cheaper than a ceramic heat emitter.....just a thought. Good luck!