I also have some of these box canyon chuckwallas. They were very hard to get started eating.I have kept them on sand but there are alot of rocks that they get between. I have had them since June and have had no problem with sand. The female did not come out for heat today or to eat but maybe she is getting ready to hibernate. Please email me off list so we can compare notes and see if these chuckwallas are from the same dealer. Please email me at jsellersiv@yahoo.com Thanks John Sellers