The door is open on this, so you can see into it. The top floor just has a fleece blanket and they dont go potty up there. The downstairs has bedding and an extension which is where their food is. They love it!
We have 4 piggies now!! We originally had 2, then adopted 2 from the shelter. They love it! They mostly hang out on bottom, but go up to the top to lounge. One never goes up on top (not sure why).
some people would argue that a 2x3 is nearly too small for one pig... But you have four living in there? Four guinea pigs will need at least a 2x6(twice the size of this). Don't mean to be rude or anything, just pointing that out.