New Flock, New Owner, RIR Hen is lethargic, tips please!

[Wynette]

Another question: I want to move my chick brooder to the shed where the coop is eventually. So they'd be next door to, sharing the same air space, with the adult chickens. Is it dangerous for them to be sharing the air space with the older chickens? How long should I wait to move the chicks?

I quarantine any birds I bring onto my property for 3 weeks. That's because by then, anything that may be lurking (disease wise) will more than likely have shown itself by then.