On a nice fall day it's pretty fun to watch a sow take her piglets out for a stroll. She's pretty protective of them -- she knows me, and I know her, but they are her piglets, after all. So a little close scrutiny from mom and she decides that I'm the same fellow she's known all her life, not some suspicious stranger, and relaxes a little.
She's a 14 nipple sow, picked when she was a piglet for that reason, and everything seems in order. The most engorged nipples are being used by the pig, the ones that aren't so engorged are not. Pigs will pick one nipple and pretty much stick with that nipple as their private one. They're not adverse to raiding some other nipple if they're given the chance.
She wanders around, snuffling at grass and shrubs, a mouthful of grass here or there, until the piglets squeal her down. They're pretty demanding. "lay down! lay down! "
And she lays down, and they all line up, and it's dinnertime. She's closing her eyes and grunting contently while they nurse. Pretty soon, around dusk, she'll go back to her shelter and all of the little pigs will follow her in a line.