Hi all! My chicks will be 2 weeks in 2 days. I have the Premier 1 heat plate which has been working great. But the last 2 nights when the chicks go to sleep they have stopped using the heat plate and just sleep in a big pile in a corner of the brooder. Thinking maybe they were too warm, I raised the plate up more on 1 side to near the top, but they still don't use it. They use it during the day to warm up while going about their chick activities just not at nightime. Should I be concerned or just let sleep in the pile?