Oh my goodness that almost sounds cruel, I would NOT close the door, maybe if you just purchased a gate, so he could at least see out the door and hear better what is going on... i think you might have a better puppy if you left him in an x pen or put a see through gate ( baby gate) at the door!! My puppy is very nosey and likes to be with us all the time I can imagine locking her in a dark room with a closed door. Sorry
