A sow that was rescued from a cage where it had lived for five years is already thriving in the open, says its owner.

Piggy Sue was bought two weeks ago for $2.50c a kilo by animal trainer Carolyn Press-McKenzie, who runs Pakuratahi Farm Animal Sanctuary in Wellington.

The sow had lived in a "disgusting" farm of 10,000 pigs. Most of its five years were spent in a sow stall, 60cm wide and 2m long - within the legal limit.

"She had pressure sores from the cage, and was emotionally switched off, with her eyes glazed over," said Ms Press-McKenzie. "The farmer said she had never been outside."

At the sanctuary, she has her own shelter, and three acres of land to share with 17 pigs. "She has adapted so quickly. She is new to walking, and to grass. She had obviously never seen rain - when it fell the other day she poked her head out of her shelter and then frolicked outside."