Please be careful with the heat lamp. So many people have lost their whole coop and babies from those things. My own heat lamp caught fire of it's own accord this winter, just burst into flames.
We had a coop fire 6 years ago from a heat lamp. So yes, they make me VERY nervous. Especially with this little group, cause we hatched these little ones. I made sure the heat lamp is very secure- it is clamped and tied.
I might end up bringing them in for the night. It's chilly out there. But the brooder was just getting way too small for them.