Depends - At 2am Star has a nasty habit of drinking and when she does she flips the ball bearing and clanks. Also if you have three in season together Astro hides.This is fab! Lucky piggies.
Don't they keep you awake? We took ours away once, 'glamping' in a little hut - never again! They're just so loud scurrying around and drinking from their water bottle even.