Putting New-to-Me Yearling Hens with Young Ones

I planned on picking up a dozen or some mixed layer hatchlings, Bardrocks, Buff Orgs, Austrias, and Americaunas in a couple of weeks then putting them in the coop/run - brand new- around the first of June.

I just got a call from a local woman who said she's moving and has 8 yearling layers - Bardrocks and Austria's - she's willing to give away. She said they are laying great right now.

What is the best way to introduce the young and yearling hens to this new coop? Would it work out to put the youngsters there first or put them all in within a day of each other?

 

Thank you. I read up on biosecurity.
The woman giving the hens away said I could come and inspect her flock/coop. I'll look for signs such as discharge from eyes, beak/nose etc. I'll read up more.
In terms of space for them all to spread out and escape bullies, I've divided my run into two sections, was thinking of annual rotations to keep vegetation available for them, but the two sides have approximately 800 square feet and 1140 square feet respectively, with sage brush, a small juniper tree, and other "obstacles" for birds to hide/seek shelter. Spanning chicken wire over top today to prevent aerial predation.

My fear is the coop. It's adequate for 10-12 regular size hens, couple with enclosed 10 x 10 run. If there's going to be trouble, this is where it will occur. I do have at least 2 new feeders and waterers so I can spread them out a bit.

You have great links on your posts - thanks so much for including those - "Ventilation" and "Space"
I included pics of the area. It's taken a lot of work but I feel pretty good about it.