Mine do that.
I once pulled 6 hens out of one box. I have no idea how they all stood for any others getting in or how they even got in. I forget what I was doing, but I was walking towards them and saw a head an feet sticking out like one was folded in half. I had to be so careful cause there was a couple of Games and the rest were FBCMs. I couldn't believe it. Later I wished I had gotten a pic, but I was too worried about getting those birds out safe. They were twisted around eachother. Wings, legs, heads, it was unreal. Three other boxes sitting there empty and they were all piled in the one.
The bins are 4 x4, so I want as much floor space as I can leave. Plus I don't want to have to open the coop to collect eggs since grandkids like to help.