Two Roos CAN live together if you introduce them slowly and if you make them bond slowly. It depends on their personalities... I know someone who has 5 roosters. Of course this is not a healthy choice, but you can make it possible. Don’t expect instant friendship though... I suggest getting some pullets if you can. Good luck!
Your best bet with just 4 hens (or pullets if they're under a year old) is to keep the cockerels (males under a year old) in a bachelor pen. Once those hormones hit and the boys reach sexual maturity, they'll harass your pullets endlessly. The girls won't get to eat, drink or dust bathe without one or both of those cockerels wanting to mate them. And in my experience, if you have more than one cockerel, they'll often gang breed a pullet-one will knock the other off and breed her himself. The pullets don't reach mating age at the same time as the cockerels, so it can also be traumatic for them that way.
