@Alaskan
I was going to triple the size of my coop to keep three breeds separate.
Now I'm thinking of just doubling it and keeping a mixed flock, and building a couple large tractors for breeding pens.
Yep, I have 2 tractors for breeding... and right now I am using the vegetable garden for "I don't want you in my breeding program" birds.
I wish I had 8 tractors.... you could use them for breeding pairs and quads etc. and also some to grow out chicks etc. etc. very practical.
Then a giant pen for winter and the time of frozen water.. but I really like 3 pens in the winter 1)ducks 2)bantams 3)standard size
I want the stupid blasted (insert curse words) leghorn chicks that I paid super big money for out of my house... and I don't have a broody to stick them under.
I bought 3 Cochins 2 years back for the SOLE purpose of being broodies. One went broody last year, exactly when I wanted her to..... but no luck this year.
I took one that looked "interested" and stuck her in a tractor with a cozy nest and eggs....
But WOW am I impatient, I am going to give her 2 hours to settle and then try her with some chicks.. (don't laugh, I know that is stupid and firmly in the land of fantasy... but it MIGHT work)

Sam, I'd go with a dirt floor and a just pour a concrete floor if you get out of chickens. Concrete will suck all the ammonia into it. I would also put up partitions already, you do't have to take them into use, you can just keep doors open, but it's a heck of a lot easier to just build them from the get go than to add them later. Plus, having walls that block site lines a bit will keep things calmer in the coop even though the birds would be allowed to move freely between the sections.
I worry about walls creating corners where chickens can get cornered and get the tar beat out of them.