My understanding is the more ventilation the better, just make sure it is draft free. There is a nice web page by Patandchickens https://www.backyardchickens.com/web/viewblog.php?id=1642-VENTILATION maybe that will help you.
Cute girls!
How hot does it get where you live? I don't see any shade trees near the coop so if it gets hot you need to plan on even more ventilation. You don't want roast chicken.