I have buff orpingtons, "HAD" white plymouth rocks, have road island reds, and barred plymouth rocks, and now a couple of baby cochins.
I have two roosters... a buff orpington, and a barred plymouth rock.
Both of my roosters get along VERY nicely, and NO they did not grow up together. When they met... they kind of duked it out... but not too badly. They did get their combs a bit bloody, but after they both got an iodine treatment, they became best buds.
I think they joined together to form the "Run Away from Humans" alliance.
Just my experience... but I think both breeds are known to be gentle... so if you do go with two roosters... go with an orpington or a plymouth rock (your color choice)
The orpingtons include... Australorps (which are just well-bred black orpingtons), white, and buff. Then there are white, barred, and partridge rocks (all plymouth rocks).
You have a mighty selection there to choose. You can probably get any color orpington, or rock rooster, then breed them with another color of the same breed, like a buff orpington rooster to a black australorp hen... you still get an orpington. See what I mean?
Also... if you mix colors like that, you may end up with various other colors... like the Blue gene coming through or something neat. I dunno... genes get tricky, but I bet you will get all kinds of colors. ^_^
Yes, your roosters will breed to whatever they can get to that calls itself hen. ^_^ So if you want a pure bred... but variety in color... you have some good options within just 1 of those breeds.
Just my non-expert, newbie experience so far.
Cricket