Can humidity or dampness be bad for a guinea pig's health in large doses? My pigs have had to move to the cellar during the recent heat wave and it's been raining a lot, making it more damp than normal down there. [Our basement never floods, but it's not finished so it is leaky.] I'm worried about their hay getting moldy-- how can you tell if it is? Or maybe them having respiratory problems. Is it worth buying a dehumidifier to avoid health problems?