I have a babygate and would let Oliver & Charlie have the whole kitchen when I had to leave the house too. Charlie ALWAYS ripped up the potty pads -- leaving poor Oliver with nowhere to go! Charlie either got bored liked people mentioned or nervous and overwhelmed by too much space (I read that happens to puppies sometimes when the area is TOO big). When I have to leave the house now, I put Charlie and Oliver in their x-pen. Charlie seems to leave his potty pad alone in there. They just snuggle up together in their bed.
I am going to let them have the whole kitchen again maybe when they get a little older??? I hope it is something he will outgrow too