From Bulbapedia, the community-driven Pokémon encyclopedia.
Whenever the player brings in one of the "Wanted Pokémon" in the game My Pokémon Ranch, Hayley will offer to trade one of her Pokémon for it, and the Pokémon received will be one of the following twenty which know a TM move, Egg move, or have something else that makes them unique. Although Hayley can bring almost any type of Pokémon to the ranch on any given day, only the Pokémon listed here will be offered.
All of these Pokémon will have the OT Hayley (English), ユカリ (Japanese), EULALIE (French), EUKALIA (Germany), GIULIA (Italian), EULALIA (Spanish) and the Trainer ID number 01000.
Note that all of the Pokémon with specific Natures cannot have a different Nature, gender, and Ability and they cannot be Shiny. The name of the Pokémon is its name in the game's language, meaning that a German Eevee would have the OT of EUKALIA and the name EVOLI.
Hayley will only trade if she has already brought one of the above Pokémon into the ranch. To get one of those Pokémon, repeatedly answer no when she asks "Is a ______ Pokémon okay?" when she asks about the Pokémon she should bring the next day. Eventually she will say she'll bring a Pokémon that she's interested in, and it will be one of these Pokémon below.
These two Pokémon are only available once certain requirements are filled.
Once 250 Pokémon are present on the ranch, it will expand and jump to a new level. When this level is obtained, Hayley will add a new Pokémon to the "Wanted" board, Leafeon. When Leafeon is brought to the ranch, she will offer to trade her Phione for it.
When 999 Pokémon are present, the ranch will expand and jump to level 25, the maximum level. Once this level is obtained, a new wanted Pokémon will be added. Hayley is now asking for any Pokémon Egg. When the Egg is brought, she will offer to trade her Mew for it.
These Pokémon were available for trade after certain people came to the ranch during the event period.
This Pokémon can be obtained by trading a Zigzagoon. Its original Trainer, ごるこ Golko is the feminine form of name of one of the Pokémon Sunday hosts, Golgo Matsumoto. A similar Octillery previously was made available at Pokémon Center stores.
This Pokémon can be obtained by trading a Starly. Its original Trainer is one of the Pokémon Sunday hosts, Baba Hiroyuki and its nickname, ババイゴン Babaigon is based on this OT and Flygon's Japanese name.
This Pokémon can be obtained by trading a Bidoof. Its original Trainer is a special guest of Pokémon Sunday, Yukina Kinoshita. This was only available with the Platinum update of the game.
This Pokémon can be obtained by trading a Magikarp. Its original Trainer is one of the Pokémon Sunday hosts, Ryuuji Akiyama. Its nickname is ジョン John. This was only available with the Platinum update of the game.
This Pokémon can be obtained by trading a Machop. Its original Trainer is one of the Pokémon Sunday hosts, Red Yoshida, also known as Professor Red. Its nickname is ホームラン Homerun. This was only available with the Platinum update of the game.