Without a picture one can't be sure, but doxies do come in tri-colour. If this was a purebred I'd laugh. This is a 4 month old, so there is a chance for training him not to roam. But you need to take the time to get to know the pup. Don't just let him free the first day. Even though you might yard train him, he won't be 100% trustable so you'll need to supervise him outside.