I'll reword that post. "I'd rather use" a heat plate over a heat lamp. It simulates a mother hen, is easily adjustable, less likely to cause fires, helps the chicks feather out more quickly, and keeps the chicks on a natural day/night cycle.
I mean...is it hot where you live? I'm shocked that they've lasted two whole weeks. Generally, the answer is YES, use a heat source. I'd rather use a heat plate over a heat lamp, but yes. Heat source is good!