No,, males can stay together, it's just that some breeds or specific roo's won't get along very well compared to others..Or some may kill, which is why it's not advised to but it's possible
If you have enough space, feed, water, sleeping space, hens ( optional ) and room to run, they should be able to live together. If there's not enough room for them, they'll fight, injure, and possibly even kill the others. ( could be from an injury or fighting ) I wouldn't recommend having them...