We're just becoming a bit worried about Rio....he still plays for up to about 10/15 minutes at a time before he goes & lies down. But he just doesn't seem very interested in much & lays down for hours at a time during the day, despite efforts of interacting with him, as well as losing his appetite. I don't know if this could be anything to do with it but he also doesn't cover his poo or wee after he's been in the litter tray. He used to until a few days ago but now doesn't seem bothered (the litter tray is cleaned out completely every few days & poo removed whenever we know that he's just been.)