Welcome to BYC.
The usual guidelines are that for each adult, standard-sized hen you need:
4 square feet in the coop,
10 square feet in the run,
1 linear foot of roost,
And 1 square foot of permanent, 24/7/365 ventilation, preferably located over the birds' heads when they're sitting on the roost.
The dimensions you have a comfortably generous for 6 hens. I can't see any ventilation in the photos, but if you've got good ventilation on the sides that aren't shown then your chickens are lucky to have such a nice coop.
Where, in general, are you located? Climate matters so if you add your location to your profile we can give better advice.