Sounds Horrible crunching noise

[Murk21]

I'm wondering if I'm becoming a paranoid guinea pig mama, but last night as we were feeding veggies during floor time, one of my pigs made this awful crunching noise and it lasted for maybe 15-20 seconds. It sounded like he was chewing on rocks and in my mind I was thinking that I was going to pick him up and find one of his teeth missing or broken. The veggies are washed really well and chopped and the floor time area is a large penned off area in our spare bedroom and isolated so I'm thinking that it'd be fairly unlikely that rocks or similar could get into the pen. Would grinding their teeth make a noise like that or do you think he picked something up and ate something he shouldn't have??

 

[cynpz]

My guinea pig is doing the same thing right now! i've only had a few days, but ive never heard him do this before? he started after i fed him a slice of fruit? im afraid to pick him up in case doing it as a warning or something? im unsure, but i hope someone replies with an answer because uneasy about him doing that? he lives alone, so i wouldnt think he'd be trying to show dominance?