I am having the SAME problem. My pop door is made out of a cabinet door that opens, well, like a cabinet door. Chickens went into the coop for 3 weeks, but now they're roosting on that door. I have to load them in every night. Not sure if it's b/c of the heat (central Texas) or b/c they're too lazy.
Just be careful about a pop door that swings sideways... They may roost on it like mine are now.
Just be careful about a pop door that swings sideways... They may roost on it like mine are now.