Disregard this, I see that you already have the young ones. Nice coop, but you need to add way more ventilation asap. Is that going to be your main coop, as in you will add the new birds to the older ones in that? (or vice versa?) Your quarantine coop NEEDS to be a different coop from where you plan to permanently house your birds. You will also want to consider how you will integrate the birds.The best way, IMO, is look but don't touch, where the birds have a divider between them for possibly weeks, to get used to each other. So, with that in mind, a separate sleeping area and run area will need to be added or set up close to your main run. After quarantine, of course, which should be a far as humanly possible, from your main run. If you can't manage this, reconsider the older birds, or wait, at least, to pick them up until you can.