Mine have paper on the floor, a layer of sawdust, some hay to sleep on (you big softy with a snuggly bed ) and more to eat. Check with your inspector that they approve of sawdust though - some gp people think it causes respiratory problems and prefer shredded paper or some horribly expensive special bedding. I suspect that's something that a pig is either prone to or not.
Ours are incredibly dense about recognizing chew sticks and treats as a food or entertainment commodity, but like to gnaw on lumps of tree, if you have such a thing available (there are loads of lists of safe woods and foodstuffs on the internet). Cardboard is popular (not coloured), and if you slit open a kitchen roll tube and fill it with hay, you have a combination hay rack/toy. Any sort of tube or box to play/sit in is irresistible.
Favourite foodstuffs here: parsley, spinach, carrot, cucumber, melon, dandelion (supposed to eat this in moderation though, also lettuce), groundsel, sow thistle, chicory, grass, grass and grass. Not lawn mowings though, as they heat up quickly and can kill them. Red peppers are supposed to be a spectacular source of vitamin C, but ours won't touch them.
It would be OTT to suggest an allotment as a gp accessory, but it's great for growing treats and for recycling the bedding...