We have been having the same problem with our 13 year old Iggy Rex. He hasn't been going more than once a day but has been pooping on his top shelf and not using his water container that he has always used in the past. He doesn't want to come out of his cage anymore and we are also very concerned about this change in behavior. Rex has become a very loveable pet and we always loved having him out of his cage. We also are very concerned about this change and what we can do to get him back to normal. Please keep us informed of any help you may receive.