Probably. You need to plan on 1 square foot of ventilation that is open 24/7 per chicken, so 5 sf for you. This does not include the people door or the pop door, as those will be closed at some point for security.it has 2 windows and a screen door....do I need to add more ventilation?
The ventilation should be up above the roost, so it's over the birds' heads. This is important in the winter; you don't want an icy draft blowing in on the birds.
A great place to add ventilation are soffits. All openings need to be covered with hardware cloth to keep out predators.