The coop is 2 feet off the ground so the inside coop is 5 feet on one side and 4 feet on the other. I was planning on using a drop board and have open vents on the top. So 5" on the top for the vent then 18" under that for the first roost, then 12" for the second roost, and 12" to the drop board. So the drop board will be just above the nest box and the first perch will be 12" above that. I hope that made sense.
However, if I used a drop board it would stretch half way across the coop so I was planning to only have it 2 feet wide so it would catch the first roost and part of the second. Whatever else falls can just be turned with the shavings every few days. I figured this may be a happy medium.
I was looking at this thread here http://www.backyardchickens.com/t/596294/post-your-chicken-coop-pictures-here/40 and saw that a lot of people did not have a lot of windows, just vents up top, and even those who did have more windows did not have an opening in front of the roost. I thought they would like the breeze in the summer but maybe not?
The run is 6x12 so that will be 14.4 sf per bird so I went a bit bigger there. In the summer they can use the yard as well.
Sorry I did not reply sooner, I did not notice another post. I added my location, thank you for the suggestion.