My own pup 6months old, was missing for a week, but with plenty of posters out and lots of leg-work we got him back.
I'd ALWAYS get the dog micro-chipped, and ear tattooed. Its the dogs only way of saying where its from.
Same here mine got stolen from its kennel at 3 months. Luckily he was microchiped and got him back a week later . The thing to do is inform everyone, wouldn't bother with the police they couldn't give a sh#t. Also dog lost are very good. Ask in local pubs, knock on doors etc. Good luck to anyone who has had there dogs taken by the scum that walks this earth