I have four rabbits and all of them are very healthy and happy. But one keeps having a runny tummy. Do you think he has a sensitive tummy? They're fed Wag muesli (small amount) loads of hay and fresh veg, carrots, parsley, celery, broccoli, kale and spring greens. Can't work out why the other three never have a bad tummy. He's also gained weight but all the others are slim. Wonder if it's linked?