Well, yours are bigger then mine, hopefully my girls wont mind though.
Our bigger boxes are 12x12x14. Most of the things I've read lead me to believe these will work fine but only time will tell. They haven't started laying yet so we shall see!
What do you mean by a "true" bantam breed? I'm a dog person so is "true" in the bird world like pure breed in the dog world? So what would the Cochin and Ameracauna Bantams be? Maybe like a designer breed? Lol. Like the Labradoodles?
It seems like it takes the Bantams longer to grow, my little ones seem like they've stopped growing but are still so tiny! My friends 1 yr old Cochin Bantam roo could swallow my two little ones, is this normal? I hope not because their small size sure makes them easy targets for my standard sized birds.