It’s a small farrowing pen with a shelter. She’s accustomed to free range foraging. I’ve read it can be boredom or even resentment. Pigs are smarter and more complex than most people think. If I release them, the five day old piglets will certainly die from exposure. If I don’t, she will likely kill and eat the rest of them. She’s in a food surplus situation so I doubt it’s hunger motivated. This is new to me, and I’ve been raising pigs on and off for fifty years.