Yes, way too small for 7. Actual, it is too small for almost any number because of the roost placement issue...
I am sorry for the bad news!
As a rule of thumb you need at the minimum 4 square feet per bird, perches need to be at least 2 inches wide, at least 1 foot per bird, more if you get hot weather. Perches need to be at least 12 inches from the wall, better is 18, there needs to be at least 4 feet space for them between the perch and the other wall to flutter down again...
Finally ventilation: at least 1 square foot per bird! In order to make sure you have adequate ventilation but also a nice protected coop and draft free perches you need to have adequate space! Best is having ventilation all along the top of the walls, open gables and a few windows that you can close in driving rain, wind or freezing cold.
The ventilation needs to be well above the perches, so the chickens don’t sit in the draft.
I would not keep the chickens in that tiny coop for longer than absolutely necessary, especially during winter. For one, inadequate ventilation will make frostbite more likely...
I am really sorry you have been misled!