How hot is too hot for chicks and when can I introduce new chicks?

[boz]

the ones in that holding pin are around 3 weeks old and the hen are 2 yr that walk around the pin I want put them together until they are over 3mo old maybe even 4 mo old

 

[rosemarythyme]

At what age could i introduce them all?

It's not so much a matter of age of the little chicks but how much time you give them with the older birds, and what your set up is like, so they can acclimate.

I have my 3 week old chicks out with the adults right now. They've been outside since 2 days old so they've seen the adults their whole life, and the adults have seen them for a few weeks now. I'm using part of my old coop as the brooder (link to it in signature), and that's now surrounded with chicken wire that's elevated off the ground with bricks in a few spots, making chick sized gaps that the adults can't get in. If the chicks are being bothered they can run under that fence for safety, plus there's multiple other obstacles in the run they can hide behind and under.

 

[WthrLady]

mine are always larger, about 12 weeks or more and that's after many protected stays outside with the rest of the flock, like in the above mini-run, and then full out with the full flock under tight supervision.