Well, it depends on your situation...
Are you planning to breed? It sounds like your planning to breed to get purebred colors. If so, you will have to keep the colors in seperate pens, so the roo's wont have contact with the other hens, or each other- thus no fighting will be possible.
Are you planning on getting chicks to start? Sometimes if they are raised together, the really bad fights can be avoided since they are familiar with each other. Note I said the really bad fights, there will still be some fighting if they are penned together, just due to hormones and dominance issues and wanting the hens to themselves.
I agree- 6 hens to 2 roos is not enough hens, unless you plan to keep the roo's locked up away from the hens except during supervized breeding times. I have about 8 roos of different ages in my flock, but one older dominate roo kinda keeps them all in line. BUT, I have at least 28 hens and pullets to help spread the 'love' around. The juvie roo's are not an issue yet, but they will be eaten soon anyways, so I dont worry to much about them bugging the hens. I dont breed, so mixed breed eggs arent an issue either.
I guess the short answer is Yes, they will fight some, over many different issues, but you can do things to help keep it from getting ugly. Its not a breed thing, its a roo thing.
