Legends (and facts) about people being eaten by pigs long predate WW2. Just a peek at out own archives show -
But AFAIK, the only WW era story specific to any of your details was the one @Peter_Morris linked earlier. I mean, the story has a certain limited plausibility, in that shipboard animals were kept for food, and probably weren’t well fed themselves, but seems more like an urban legend rather than documented fact. Especially if it was a throwaway line, or someone repeating something they themselves had only heard 2nd/3rd/etc hand.