So my little foster bunny Thor is making small tooth noises when nobody is touching him. It doesn't seem like he's grinding in pain...not quite that loud. His behavior doesn't support that either as he is running around doing zoomies and begging...more like demanding gently for pets. But I can hear it when he is a couple feet away from me and I'm not petting him. Do they tooth pur when they aren't being pet? Could he be grinding and still acting happy? Oh and I should add that he recently had a healthy vet exam. Just a little concerned. Thanks!