
Good advice on the heat lamp from the previous greeters. An easy way to tell if your chicks are comfortable is to observe them...if they are all huddled directly under the heat source, they're probably chilly and if they are all as far away from the heat source as they can get, they're too warm. You want to see them comfortably moving in and out of the warm spots.
Best wishes with your new flock of littles!