foaming mouth

Question
My 3 yr. old spayed female has always continually made nibbling movements with her lips.  This results in white foam around her mouth area. Is this normal?  She has seen a vet, but didn't ask about this.  She is healthy in all respects.  She has done this since she was a young pig.

Answer
Yes, the foam is normal. She might also squeak or grind her teeth while she's doing this.

Intact male pigs can foam so much it looks like they are wearing a bubble beard, and dribble damp foam bubbles as they walk.

Spayed and neutered pigs don't foam nearly as much. They tend to foam when they're really excited or upset, or smelling something really good. Like other quirky pig habits, some pigs do this a lot, other pigs rarely foam up.

My guess is when your pig does this she's thinking about a treat, or smelling something tasty. Sometimes pigs will play with a special treat or explore a new one by nibbling a bit with the lips, then breathing quickly in and out to taste the the odor, then nibbling again.