Hi Eileen, Welcome to the Forum.
I feed my piggies a wide variety of veggies inc. Lettuce (most types but not Iceberg), Carrots, Celery, Cucumber, Melon (inc. skin), Kale, Cabbage, Cauli Leaves & Florets, Apple (1/4 between 6 of them), Parsley, Peppers (Any colour but they prefer red), Sweet Corn (complete with outer sheath, they're almost finished now), Tomatoes (small amount), Fresh Grass, Dandelions (including flower) & Plantain (either broad or long leaf). There's lots of other things you can you but not Potatoes or Onions. Don't forget plenty of hay as this should make up over 3/4 or their input.