Sometimes I would find one on the ground, and sometimes Kaos would eat them.

I watched one fall out on my bed, and went to grab it and he beat me to it and swallowed it. (I was a nervous wreck but he turned out all right.) LOL
Good question though. I've had a few different breed pups growing up and I would just remember them being gone, and I would sometimes find one or two in the rug.