A detail worth discussing is the opening chicks use to go between adult area and their own. There may be tricks to it that promote more fluid movement back and forth by chicks. It has been some time since I kept broods in close confinement with adults that are not kin but it did involve something that approached a creep feeder setup like used with cattle. Chicks could enter and leave around entire perimeter of adult enclosure. I will try to make something similar using wooden dowels.If chicks have what I like to call a "panic room", where only they can fit the entrances (and there should be more than one), it not only provides optimal safety, but it helps develop self confidence in the chicks so they're better adjusted going forward. Food and water is inside this panic room so the chicks don't have to be stressed and fearful trying to compete for essentials. It's a place for them to relax and be themselves without having to be on guard all the time. Almost eight years ago, when I was introducing my first three baby chicks to my two adult hens, I quickly came to the conclusion I needed some sort of safe pen for the babies if only to keep the adult hens from taking over the chicks' food. I tacked up a small enclosure in one corner of the run, and made a small opening into it that the hens couldn't fit through. By that time one hen had developed a real fondness for the chick food and I found her stuck in the opening leisurely finishing off the chick starter. So I tore the pen down and built a larger enclosure so I could get the food farther away from the openings. Later on, I built a new run and incorporated a chick pen or panic room into it as a permanent feature. Then I created small chick portals in every partition in the run where a chick might get trapped against a wall or stuck in a corner with no escape. This provides safety for baby chicks so they can have free access to the entire run and still have a safe place that they can use until they're around three months old. Currently, I'm using the panic room for a two-year old abandoned hen I just adopted, so it's anything but wasted space. Everyone who utilizes a panic room for their chicks have had peace of mind and no casualties. I highly recommend it.
They will to some degree, but if they become familiar with them through a fence first it will make the introduction easier. So plan on a temporary pen to house new ones in either next to or within your coop for a couple of weeks, after your chicks are fully feathered, around 8-10 weeks of age.
I, and several others, have played with several 'tiny door' iterations.
