thinks that they can pick up and move and jump on I'm not fond of due to a very freak accident I had here. Personally I like something that is more stable and sturdy.
I had a polish boy named Dusty Miller, he was very small and an the extra large igloo was big enough for him to hid in and jump on. he liked to move it around tip it over put it in his litter box., One day her placed it on his litter box and decided to jump ontop of it, because it was tieetering ontop the litter box it was very unstable and he fell off landing on his head and neck just right that he broke his neck and died instantly.
I was quite distraut about it and the vet said to me, he was playing having a good time, and it was so quick he probally never even knew what happened.. very freak accident, but I tossed the thing into the trash, only sturdy things for my buns to climb on. If they fall off that then they are just being stupid, but I wont risk them thinking they are doing something fun and safe and have that happen again.
on the flip side I had one bun climb up items in my house till she was 4 feet high jump off land on her mouth and nose and only suffer a cut to her lip from her teeth hitting her lip at impact. go figure.