If the concern about free ranging is predators but you have the space in your yard, look into electric poultry fence. It keeps chickens in and ground predators out and it's mobile and modular. To determine what breeds of chickens, you can post pictures in the appropriate forum on here and people...
Do you plan to let them out to free range at all or are they bantams? Because my coop/run is similar in size and it's a little cramped for 6 full size chickens. They may be OK since they're growing up together. Be sure they have plenty of roost space.