I have noticed that toys seem to be missing also... and then they show back up! it's weird because I clean my floors alot so Chewy isn't able to eat anything he isn't supossed to! But your right.
I also notice that I have to go through the toys pretty often because when chewy finds things he isn't supossed to have he will hid e it in with the toys in his toy box so we don't notice!!! I find things like pine needles, chewed paper... things like that stuffed in with his toys... is he really that smart? I guess so!