So this morning I happen to see a piece of what looks to be poop in my ball's tank. Because I'm running late I think to myself "hey I'll just get to it when I get home" just because I figure he never seems to leave his hide anyway during the day and I'm already late to class. However, I get home and the stool is missing, and it also happens to be lingering around the spot?? I feed him once a week and happened to be a day or so late because of refrigeration issues with what I had in store going bad. He eats perfectly fine and I'm sure what I feed him is good size.

Is it possible he did eat his own poop? I searched the tank, flipping over things and sifting through the substrate but could not find it. Please help.