Oranges are really good for piggies because of the high vitamin C content. I never knew that they could cause sores. Both of my boys don't like oranges, so that's not a problem for me. And like cali said, FEED 'EM THE DARK LEAFY GREENS!!!! Mine both love kale, and it has lots of vit. C which is vital to the pigs health. They love parsley and carrots too