There is a difference between "huddling" and sleeping in a pile. If the chicks are collecting in a group during the day rather than moving around, chances are they're too warm or too cold. If this huddling is far from the heat lamp, too warm; under it they're too cold. Normally they should be spread out doing whatever it is that little chicks do and only coming into the warm area if they feel chilled. Again, if you've ever watched chicks with a biddie, that's what they do.
The night time pile is another thing entirely. They seem to like getting together to sleep, something they will continue to do even after they've feathered out.
