I ended up yanking the upper part off because it was too hard on me to clean the bottom floor.
But they like it just the same. The piggies only went upstairs to steal carrots and left their greens alone in the kitchen. So now, they have a kitchen corner, which basically means that one runs over and grabs what he wants and drags it to a hidey, and the other one sits in it like a good boy and eats and does his business.