Special Codes to Unlock Things
On the far right side of your room, there is a bulletin board. When highlighted by the Wiimote, it says enter special codes. Press the A button.

Get 1 Adoption Coin: ADOPTONE
Get enough Adoption Coins to buy every available dog: ADOPTALL
Toggle unlock the Special Skin for all of your Dogz: DOGZZKIN
Unlock the Border Collie dog: BCUMSC
Unlock the Jack Russell Terrier dog: JRUMSC
Unlock the West Highland Terrier dog: WTUMSC

Game info
publisher: Ubisoft
developer: Ubisoft Montreal
genre: Simulation