It would depend on how large the cage is and maybe how old the birds are, also if they have already being housed together. I have pairs in each outdoor aviary and 2 young boys in an aviary. I know of breeders who keep all hens in one and males in the other and pair them up come breeding time, Others keep breeding pairs together all the time. I guess it would depend on how young they are and if they have been together for some time.
I bought 3 IRNs (2 male, 1 female) early last year and they were housed together BEFORE I had them so I left them together, but the green male was already paired with the female and chased the blue male around. The cage was big enough for the blue to keep his distance and have his own space but I ended up giving him his own aviary...and a new girl to-boot!!!

I think maybe around breeding season things might get a bit feisty.