(Yeah, poop could accumulate, I thought of that too, but the plywood corners don't extend so far that we can't get inside to clean if we like)
I added a third concrete block at the bottom, but didn't move the top. This morning I was actually able to observe them coming out (usually they take their time coming out after I open the door). Two of them walked down the ramp, but, as folks suggested might be the case, they spent a bunch of time thinking about jumping on to it, and one of the ones that flew down didn't like it and probably would have used the ramp if the attachment point were easier. I might try to add another piece on top of the frame that holds up the door, or add attachment points to the door. The former would be better if I can figure out a way to do it, as then I wouldn't have to move it every day.
I added a third concrete block at the bottom, but didn't move the top. This morning I was actually able to observe them coming out (usually they take their time coming out after I open the door). Two of them walked down the ramp, but, as folks suggested might be the case, they spent a bunch of time thinking about jumping on to it, and one of the ones that flew down didn't like it and probably would have used the ramp if the attachment point were easier. I might try to add another piece on top of the frame that holds up the door, or add attachment points to the door. The former would be better if I can figure out a way to do it, as then I wouldn't have to move it every day.