I'm a bit confused because when I have lap time with my piggies they sometimes pur. I always thought that this means they are happy but something I've just read makes me wonder if its actually because they are frightened.
("rumblestrutting"hehe, I've never heard it called that before! You made me giggle out loud!
Of course, every pig is different! But mine do the 'Brrrgh' noise when they hear or see something unusual. They also do it when I stroke them sometimes. And I know they're not doing it because they're displeased or uncomfortable, because they tend to get snappy if I do something they dont like.
Its the long cat like purring that they make. They do stretch out like little cats too. I'm positive that they are happy