My almost 8 week old has the funniest habit! She's the only one who has ever done it quite like this. When I take her outside to potty ( she is still training) she will find these little pieces of mulch, twigs, plastic, whatever and take them up to the door and set them down. I thought she intended to take them inside when we went in, but she just stashes them and leaves them. Inside the house things started coming up missing... A friends phone charger, water bowl, socks, all sorts of things. Then we I saw her grab a leash and run as fast as she can behind the bed. I looked, and sure enough, everything was there. None of it was chewed up, either. She just stashes the stuff and leaves it ther for who knows what.