As long as they've been brought up together, are NEVER separated from the group - even for a few hours - and have reasonable space then yes, you can house them together temporarily without guaranteed death.
This depends on breed and parenting, however.
At one stage I had 20 Australorp cockerels housed in a decent-sized - but not enormous - pen. They were all pushing 10 months old and had been housed together continuously all their lives. There was scrapping but no major injuries (I know this because most of them are now sitting in our freezer
). However, one boy escaped early on and got himself into another of my pens, where I already had two roosters - we found him and thought he'd escaped recently and threw him back in.
2mins later, I rescued him from the thumping-to-the-certain-death he was getting. He'd been out of the pen almost a full week, and the others were NOT having it ...
I had one flock which successfully permanently ran two roosters, and I'm trying to do it again but with less success. Requirements:
* LARGE pen.
Mine's a minimum of 100m round, which is at least 650 square metres. Huge coop at night. Both roosters slept in the coop but on different roosts.
* Shrubbery/undergrowth/hiding places
. The trick is "out of sight, out of mind". If the dominant rooster can't see the less-dominant, he won't try to kill it. If the less-dominant can run and hide, he's not going to get the tar beaten out of him.
* Enough hens to roosters
. My flock was about 30 hens, two roosters. Some chooks preferred one, some the other. Joseph (less dominant) could play with girls up one corner, completely hidden from view and sight from Dale, 30 metres away.
* Calm breeds
. Joseph was Barnie/Araucana, of a line of calm, placid roosters who don't find young cockerels a threat. Joseph was Wyandotte x, without a vicious bone in his body.
* Grow up together
. That is, either the same or similar hatch age and introduced when still peeping chicks, or one introduced to the pen as a peeping chick, which your average rooster will ignore or even be paternal toward. The Barnie/Aras are particularly paternal, and the tolerance seems to last their entire lives - as long as there's no separation.
* Never separate them for longer than about 24 hours
. I got away with separating Dale for about three days, when he was almost killed by a tapeworm, because he was dominant and Joseph was barely crowing. They did challenge when Dale went back in the pen, and we did intervene to be sure. We got away with it, I think, because
Dale was dominant. I'm not so sure Dale would have tolerated Joseph going out and coming back in again.
I've got three boys in a tractor awaiting the freezer; they've been there about three weeks and that's about their limit. They're starting to scrap. They'll be processed this weekend.