I agree with some top ventialtion. It looks like there is an overhang on each end. So maybe you could put in vents where the red box is drawn. Cover with HW cloth.You need ventilation at the top because heat and ammonia both rise.
1 square foot per bird is generally considered the minimum, but in a hot climate more is better.
I also agree with windows Let in more light. We have windows open year round. The run protects them from letting in rain and snow.