I have a coop/run that's approx 12' x 5'. The structure itself is predator proof (as much as I can make it). It has hardware cloth sides, hardware cloth dug into the trenches, multiple locks on all of the exterior doors and flashing nighttime "eyes" that start when the sun goes down. In other words, the exterior of the building itself is as safe as I can make it and locked up tight. This is an urban scenario, so my girls will NOT be free ranging in the yard...they will ALWAYS be inside of this secure run. At night, the girls go "upstairs" to the roosting bars...there is a ramp (inside of the secure coop) that goes to the coop/roosting bars. At the top of the ramp, there is a sliding door--this is all within the secure coop. Is it a necessity to slide this door shut every night? I know sliding this door shut is an extra layer of protection, but wondering if it's necessary to be closed every night if it's within the secure structure? Help please!