Is that the measurements for the whole prefab or just the shelter part? Only the enclosed shelter, where the nest boxes and roosts are counts as 'coop' space. And nest boxes should not be included in that measurement. The open air portion is considered a run space.
She's a Brahma mix, standard sized. If she were batam, she'd be half the size of the others. The 'coop' is the enclosed shelter. Not the entire coop/run combo. The coop part is not big enough.
I don't see any bantam birds. I see 4 large breed birds, all about the same size in your pic. And that coop is seriously lacking ventilation for that kind of heat.
Black sexlinks and wyandottes are large breeds needing about 5 sq ft of coop space per bird. And you need at least 4 linear feet of...