I do not quarantine newcomers, but I DO segregate them for about a month. I didn't have enough space to keep new birds far enough away for a true quarantine (as some stuff is airborne). However, new birds get their own segregation pen with attached coop, their own feed and waterers. These pens are not big enough to be considered a "run" so the newcomers have to see other chickens ranging around them, freely. And dream of the day they aren't cramped in their segregation coop...
But it lets them see, hear, and puff up at each other through the wire pen walls. Come the day I let out the new bird(s), they are no longer strangers and the establishment of the new pecking order is seldom more than a bit of a peck, a feather pull here and there, and maybe some neck feather ruffling with a few squawks.
However, the only time I am introducing more than 3 birds is when I have a brooder full of "tween-aged" chicks to integrate into the flock. I've never brought home multiple adult birds.
i do something similar. i have two 8x16 pens on the side of my layer run. adopted hens and my pullets are put into those. after some months we open the run door for one and alllow the new birds to check out the layer areas for a couple of hours while the ladies are out ranging. we usually do the transistional phase for a couple of weekends then when we feel they are ready leave the side run gate open to allow them to mingle. often the new birds will continue to return to the side run and eventually all develop new roosting routine. new cockerals and roosters are isolated in smaller pens till we decide who to keep.
I have 5 adult layers and a batch in brood in the shop. By the time I have to integrate the new birds I will have built a new coop and run. My plan is to have a 10x12 coop complete with vents up high, a pop door and 2 sliding human doors, multiple waterers and feeders. The run is to be 30x60 segregated down the middle all the way to the rear of the coop with a sliding hatch door that I control. There will be 2 outside access doors, one for each side of the run. I also will have 2 sets of nesting boxes of 8 each. My question is, is it better to have one large roosting area or can I divide it into seperate roosts?
I have two, wide ladder roosts in my former garage-now-coop. They're attached to the wall(s) with hinges so I can raise them to clean under them. Although my dominant rooster will check out both ladder roosts, he sleeps on the top rung of His Roost, with His ladies. Middle ranking birds sleep up high on the second ladder roost. Youngsters sleep on both, middle or lower rungs.
Don't see why more than one roost won't work for your set-up, too.