To be clear, I don't generally have 11 at a time. We currently have 5 permanent residents, and a rotating cast of foster cats who get their own room - all incoming animals need an initial 2 week quarantine, even if they seem healthy at their initial vet check, just in case the stress of travel and a new place brings out some kind of illness that they're carrying.11 CATS. Oh the disruption lol. Just one of them can cause such a huge mess. Me yelling when I heard a bang or something "Sasha what'd you do?" was a normal occurrence. Her answer was always a little "meow". I can't imagine 11.
Beyond that, I generally don't let them into the rest of the house because some of mine dislike new cats, so there's no point going through that stress if they're not going to stay.