A few people I've talked to from Louisiana have said they are big enough to stay in the pen/coop with a heat lamp but I think I'm going to wait a little longer before putting them out there permanently. It's nearly 75 degrees today but its still frosting over night. They are so funny to watch out there though! My daughter is really enjoying spending time with them in the pen!
I put my 19 mixed flock (almost 5 week old) in run again today and will not put them back in brooder. It was 75 today 45 tonight and 78 tomorrow. I will let them have the heat lamp for a few more night's. It has been so enjoyable watching them learn all the new stuff. It will be interesting to see if they go in the coop tonight. A few already went up the ramp a few times and looked in. I am a Chicken Freak for sure!!
I put my chicks out last night and they won't come back in either. They made it through the night with the heat lamp and didn't have any uninvited guests last night either! Yay! We are supposed to have a cold night or two in about a week (down around 40) but with the heat lamp I'm sure they will be fine.