some advice needed please, I have a 15 month old jack russell who sleeps for up to 15 hours a time without getting up for any thing not even the door bell going will stir him. Our vet said its nothing to worry about he is just very chilled out!? Is this normal? even a 20 min walk leaves him shattered, hes not over weight, and half the time cant even be bothered to chase a ball. All advice and thoughts welcome.