Behavior Nibbling pigs

[piggdaddy]

So I have three guinea pigs who I've had for a few months now. Two of them like me well enough, they wheek for me, will eat out of my hand and popcorn when I talk to them. One of them is just sheepish. The two more outgoing pigs however, have a tendency to nibble. I'm curious, because whenever I offer my hand for them to sniff, they'll take a whiff shortly before starting to nibble. They'll nibble a little before biting down harder so that it hurts. Should anyone know why they do it? They're in their cage, not scared, and have no skin condition. Also my hands don't smell like food. I'll try to pet their heads but their mouths follow my finger for a nibble. They've never bit me put of fear/malice/necessity but I'm not sure I get why they do this

 

[CavyTV]

How old are they? Younger pigs tend to have that bad habit of nibbling fingers. It should pass. I find that my Flynn does the same things, only when I've just eaten something with my hands or I just got done handling/preparing food. Your hands may not smell like food to you, and you may have handled/touched/prepared/eaten food a while ago, but to them, they can still smell it as their noses are much stronger than ours.

 

[piggdaddy]

They're about 7 or 8 months old lol