You currently have your whole flock indoors don’t you? I’d focus on building a stable coop that can handle your winters before adding more birds. Sounds like chicken math has taken over your life. I couldn’t live that way. So much dust, it can’t be good for you or your birds. Keep an eye out for respiratory infection in your chickens. It happens when overcrowding and inhalation of dust happens for long periods of time. Since they’ve been inside in cages with little fresh air for so long I’d say your at high risk for it.
The bigger ones are in a 5x15 or so enclosure with a roost bar and all(no cages). The babies are in an x-x large dog crate. Windows are open, heat vents are closed and air purifier is on. The dust is well under control. It's no different then if they were outdoors in a coop. The big ones will be going back outside soon and small ones moving to that bigger indoor run while I build whatever I got to build. The coop was not the problem, it was the netting versus a roof on the run. I'm starting that within the next couple weeks. If I can get away with putting all together(minus the boys) I will-just not sure how that will play out.