Is it really necessary to keep new chicks quarantined for a while when integrating them into an established flock? I have four 5 week old chicks and three 4 week old chicks, and then an established flock of eight 9 month old chickens. Chicks are still in the brooder but will need to go to the coop soon. I don't have a very convenient way of creating a barrier within the coop, and it's getting cold here in Northern Utah so I can't keep them separated outside in the run all the time either. Has anyone had luck with just putting younger chickens in with an established flock with no separation, or is that asking for trouble?