Hey I found this out
Additionally, each day Hayley will give the player requests for certain Pokémon not in the player's Pokédex to be added to the ranch, along with clues on where to find them in Diamond and Pearl. It has also been confirmed that you can obtain a special Mew and Phione through a trade. Upon fulfilling these requests, the player will gain new items such as a bell that calls the Pokémon to the player. Hayley can also trade certain Pokémon she already has in her possession. Eventually, adding more Pokémon to the ranch unlocks new features to the game and expands the ranch.