You can put multiple breeds in one coop, particularly if they are docile breeds. Game breeds tend to be aggressive. Mediterranean breeds like Leghorns, Minorcas, Anconas, etc. tend to be high strung ,flighty, and noisy. Most dual purpose breeds are docile although sometimes Rhode Island Reds can be aggressive (especially the roosters). Breeds like Plymouth Rocks and Wyandottes are normally docile, although I've occasionally had to cull one from my flock for aggression. Easter Eggers (often incorrectly marketed by hatcheries as Ameraucanas or Araucanas) are normally docile, but don't usually like being handled (there are exceptions) and can be very noisy. The crested breeds like Polish and Houdans are normally docile but because of their head crests and poor vision tend to get badly bullied by other full sized breeds. Sex Links (both Black and Red varieties) are generally friendly and docile egg laying machines, but they can be really noisy at times. The English breeds (Australorps, Orpingtons, Sussex, etc.) and the Asiatic breeds (all gentle giants such as Brahmas, Cochins, and Langshangs) are almost always calm and quiet (for chickens), and very cold hardy to boot. You would not likely have temperament problems with any breeds from these two classes.