New chicken roosting issues

[Synthlady]

Have you tried placing your new hen on the roost with your flock (at nighttime when they can't see) so that they can wake up together?
Otherwise, I would suggest not using the cardboard and provide a separate roosting bar within the same coop.
It's always easier to introduce a group of new chickens to the flock than a single one. When they already have a friend, they stick together and don't get too stressed, because they have each other. So if you want to add a chicken, I would suggest add BFF* chickens instead (2 or more).
Let us know if any solution worked, I would be interested to know.

*best friends forever

 

[Mrs. K]

That is more than enough room for 4 chickens and it looks like two roosting bars. At that height, they don't need a ladder, they should just fly up there? Mine have never had a ladder and do just fine.

I think that there maybe some squabbling at dark, but I think it will settle quickly, and they will get over it. I would leave the cardboard up. But I would be real surprised if they use it.

Mrs K