Yes, the main door is hooked open for most of the year. It gets shut for the winter. Yeah, you could just build a wall of hardware cloth to partition the coop. But I would wall of the whole back 6'. A 6X12' space would be much better. The you don't have to build two walls, just the one. And yes, as long as you build a proper, hardware cloth screen covered wall, you could leave the front doors open. The chickens would be safe from everything, short of a bear.
Ok so to sum up my ventilation decision: I will put two large vents on both the east and west side up by the roof line. In the summer I will leave the front doors open and the two windows. Do you think I will have enough ventilation in the winter? The two doors and two windows will be closed. That will leave two large vents up by the roof line(east and west) and also I forgot to mention there are already two small roof vents on the roof that previous owner installed to vent the shed.
Edited by amijab - 3/17/17 at 9:23pm