Things to consider:
*The breeds you choose - some bantam breeds are HIGHLY active, and need more space. Other ban. breeds (silkies for example) are more low key, and can handle not having ample space better.
*Your location (didn't see it listed) - An area that gets "real" winters needs more indoor space, as the birds will spend quite a bit more time indoors over the winter months. But in areas with year round mild weather, the birds are literally ONLY inside to roost or lay eggs.
*Whether they'll be contained 24/7 within the coop, or whether they'll spend a few hours out of the run each day. Most say bantams can tolerate less than the 10 sq. ft each run space minimum suggested for LF breeds. But I can't even see 10 sq. ft. each being enough unless they get out for a few hours a day to peck about and stretch their wings.
