That doesn't look like a lot of space to work with, so that's why you're having a tough time.This photo is taken from above in .5 mode. This welded wire divides the tall part of the run down the diagonal, and is four feet tall. Despite my efforts to open the “door” of it (aka unhooking it from the side farthest from the food) without using my hands as a chicken would, I have not been able to. I don’t understand how they did it yesterday.
I'm betting the younger birds are just going over the top to get out, and then maybe trying to squeeze back in afterwards, if you're finding the fencing dislodged on sides.
Can you possibly borrow a large wire dog crate from someone and use that instead? Would be far easier to access, be a bit more out of the way, and escape free.