Hi Anlicia!
Our little ones are 3 and 4 weeks old and like yours, going stir crazy in the brooder. Now we've been letting them outside a lot during the day, but we akways brought them back in just before dusk. So tonight is their first night in their coop!
We have been using the MHP method instead of the light bulb. So we put the heating pad in there. When we first checked on them (about 7pm) they were in the run underneath huddled in a corner. So we picked them up, placed them in the coop, moved their food and water in too, and closed the door.
Checked on them again about 8:30pm. They were not on or under their MHP but huddled on the cold floor near their water. I moved them on top of the MHP but the light from my headlamp got them all wound up. So I just left them a while to calm down in the dark (and cold).
About 10pm I went out again and wised up, using my light only briefly to ascertain their location in the coop. They were in a far corner near their food this time. (!!!) I turned off my light before the crazy chicks woke up much, then lifted each one to on top of the MHP. They didn't squirm and protest nearly as much as before. I quickly left them.
Just checked on them at 11:00pm and they were all on the MHP! Whew!!
So... with adequate heating they'd probably be fine, even at this young age. I am in SoCal and it is in the high 40s tonight. My MHP is set to medium. My chicks and their brooder have been in our den and our temps in the house are a pretty consistent 68-71°F. But as I said before, we have given them lots of outdoors time, even on cold and windy days, so hopefully they are semi-acclimated.
Here's a pic of them from this afternoon - a cold, drizzly day and they needed a warm up after playing in their new coop and run: