putting chicks in coop with hens and rooster

If they are getting close to the same size you can out them in. If they are considerably smaller, I would put them in a dog crate or something like that in the coop. Some way they can be with everyone, but are protected. If you do that and they are in the coop you wouldn't need to worry about the temp.

 

I don't think I would unless they have already spent time togather... I have 19 chicks that are 5 weeks old, they are in the same area as the 13 hens and rooster but they are seperated by chicken wire. at this point until I can spend time out there I wont even allow them to free range togather. Seems I heard somewhere not to introduce motherless chicks to the flock until they quit chirping, might be wrong tho...

 

6 weeks is pretty young, so I would not attempt this unless they free range most of day, so young ones can keep their distance from big ones and gradually integrate. If they are confined, I would not mix them yet. If you do decide to mix them, whether they are confined or free-range, be prepared to scoop up young ones just in case. I don't confine young ones with old ones until young ones are about ready to lay, at which point they're about full grown.