Looking at the dimensions, I think the original probably has 3 feet by 3 feet of "house" part (not counting nestboxes), which makes 9 square feet. If you need 4 square feet per large hen or 2 square feet per bantam, that would be enough for about 2 large hens, or 4 bantams.
I went and looked at...
How much floor space is partly determined by the size of the chickens. Seramas vs. Jersey Giants require vastly different amounts!
Are you asking if your enlarged version is large enough, or if the original size could ever fit six?