1. You shouldn't focus on fruit too much since it is high in sugar. Focus on leafy greens like romaine, red/green leaf lettuce, dandelion greens, red chard, cilantro, endive, escarole etc. The darker the leafy green the better for vitamin c. the key is variety. Feed him a wide variety of different greens and you'll be able to see what he likes and what he doesn't.

2. I noticed my pigs nibble on their bedding shortly after it is freshly changed. Does your pig have hay to eat 24 hours a day? Hay is very important and may get your pig to stop eating it's bedding.

3. Your pig hopping crazily is him pop-corning. He is just happy and letting you know it.

Also, Roozy recommended a very good guinea pig feed. I feed all my pigs Oxbow because it has stable vitamin C which is essential to pigs.