It's better to have fat wee piggies as when they start losing weight it's the end of the road happened with all 6 of my gps I lost we fed them baby food but none of them pulled through sadly so I'd say fat happy healthy piggies enjoying life
I would let mine out to run about indoors they loved it popcorning away and there wee chirps they love outdoors on grass but would need supervision as they can be wee menaces and escape lol