I had a small coop made by our high school carpentry class and there are heavy-duty wired doors on either side of the coop. One door will be the entrance into the secured run, the other door apparently is where I am to slide out the metal tray for cleaning or allow them out to free range. I am pretty nervous about the one door that will always be the easiest access by any predators like racoons, possums, etc. Here is a picture most resembling the type of sliding bolt latch they used but I'm sure there must be something more secure that I can replace it with. Any other suggestions? Or can I add some kind of a lock in addition to using this type of latch? Thanks for any advice given.