my "coop" is an old shed transformed. We had a coon problem too, and its fixed now. I learned the hard way....
I could not figure out how they were getting in, but every day for 5-6 days I had a dead chicken INSIDE the coop, missing head, missing crop, big mess. I thought it was a weasle or rats or something, because i could not find a hole bigger than an inch or so and I know weasles are masters of getting into small openings, although we dont really have them around here.
I borrowed my friends motion activated wildlife camera he uses to scout deer during the non-hunting season. That night we got our answer....
Mama coon and 3 babies...Mama would pry the shed doors open just enough to let the kits be able to squeeze in the crack. baby coons would go in and get dinner, and then she would let them back out.
A little "soda of death" and the coons were eliminated (I DO NOT recommend soda of death for you in the city... you dont want to kill your neighbors cat) A trap will do nicely. I have best luck baiting raccoons with sweet bait, marshmallows or honey or jelly on bread works great
Coons are sneaky, and determined, and smart. I still have the same coop/shed, but we put 5 latches and padlock on top and bottom latches on the door now, so they cannot be pried from the top, bottom or anywhere else for that matter. Its a pain, but its what needed to be done for us out here.