I was so scared last weekend with the new chicks. We had 16, 3-4 day olds set up in the brooder that the bigger chicks were in until they moved outside. Obviously more space to heat. However, they are inside, but we have a woodstove and temps at night before bed are drastically warmer than when we wake up in the morning. I noticed that the temps were dropping down to 70 degrees in the middle of the brooder and staying around 80 under the heat lamp. But lowering the heat lamp before bed made the temps far too warm, so I just left it. They were always huddled together under the heat lamp in the morning, but were never piled. The only thing I noticed is that they are getting feathers faster than the last batch of chicks that were raised, but all are healthy and alert, eating, drinking, and pooping well. Haven't lost a single one. I figure momma would have them out during the day at their age in far cooler temps.
