It killed my guinea pig in 4 days time!! There was nothing at all wrong with him so he was not just sick or old I will tell you exactly what happened. He got his head stuck in the gap under the divided slat up top! We found him laying on his side, head stuck, kicking & almost lifeless!! Within 5 mins after getting him free & holding him he died in my arms while my 10yr old was hysterical! 
I spent $150 on something that killed my sons best friend in less than a week!!