I just went in and checked on my 4 wk old chicks and noticed they were all bunched in a corner close to a night light I have in the room. Just this morning I decided to turn off their heat lamp for the first time and they have been fine but now they are like this. I feel like they are acting like they are cold so I turned it back on. Is it normal behavior at this age for them to still huddle together if they are chilly??