Can you provide some pics. Form your description, I'm a bit worried for your chickens. Have you read all of the "Oh my god, something killed most of my chickens last night" posts? From the experiences on this site, an coop that can't close lets the chickens sleep in the run. Chickens that sleep in the run, sleep next to the wire, on top of each other. All huddled together. A raccoon then pulls over half the chickens through the chicken wire in a bloody mess. I could be wrong, but an enclosed coop that closes with good ventilation might be a better idea. Everything kills chickens.
Riki
Riki