They need to establish dominance (AKA who's in charge and who's second in charge) so I would say don't separate them unless they have a bloody fight. I have two roosters and one must have challenged the other's dominance, they were both covered in blood but they didn't get permanently damaged. The dominant one (Americana) still hasn't grown back his beard and muff yet. I separated them for a couple weeks and after that there hasn't been any cockfights, a little bit of pecking, but that's expected. They weren't raised together like yours are so they probably won't get in that big of fights and mine also had a one year age difference.
About the Americanas (they're also known as Easter Eggers), everyone I've met has said that they make the meanest roosters, but I've had 5 (all at different years and 4 died at 1-2 yrs old of things like dogs and drowning, so far they're really disease resistant and only one of them was vaccinated) All of them would let me hold them and they would eat from my hand. Am I just lucky, or are all my friends unlucky? Anyway, the Americanas are not the usual ones to start the cockfights, the one who challenged dominance was a Rhode Island.
So I would keep them together because they need to establish dominance and they need to claim parts of their new enclosure. Keep an eye on them to make sure it doesn't get to big though. Good luck!