My flock only uses these 3 bottom nesting boxes and was wondering the 3 on top if I could just get rid of these 2 walls. They only use the top as a jumping area to get to the roosts. If I get rid of the walls can I fill it with sand so when they poop? They just use those to poop in and to make it easier for me. I dont know what I'm trying to say. It's hard typing things.