So, I have 28 chicks just shy of 4 and 5 weeks old (8 going on 5 and 20 going on 4). Until today, they have slept comforably scattered throughout the brooder. Tonight I went in there at dusk to change water and such and they were all piled up in a corner on top of one another. It was plenty warm in there (I just recently changed from a 250w red lamp to a 150w CHE). They seem to like the darkness and sleep all night now that they have the CHE (unlike the red light... they partied all night ) They seemed comfy and were trilling and all cuddled up. Do I need to worry as much about them crushing one another now that they are older? Why would they do this now? Is this pecking order behavior? The few who were on the rooseting bars were also knocking one another off the bar and going under one another. Thoughts? I am perplexed.