Cojiro

Cojiro is a mysterious blue Cucco which appears in Ocarina fo Time, and is Step 2 in the Biggoron's Sword Trading Quest.

Characteristics
Cojiro has blue feathers, but is otherwise fairly similar in appearance to other OoT cuccos. Another of his traits is that only "nice guys" can encourage him to crow.

Origins
Cojiro originally belonged to the mysterious man sitting under the tree in Kakariko Village, one of the few people able to make him crow. Seven years later, the man had left the village for the Lost Woods, but had left the Cucco with his sister.

Use in the Trading Quest
After proving his ability as a Cucco handler by making the Pocket Cucco happy, Link received Cojiro from the Cucco Lady. Since the departure of the original owner, Cojiro had not crowed, and it was hoped that Link would be able to make Cojiro happy again. When Link brought Cojiro to the man in the Lost Woods, the man saw that Link could make Cojiro crow, and realised that Link must therefore be a nice guy. He took Cojiro back, and, now trusting Link after establishing he was a "nice guy", asked Link to take the Odd Mushroom to the old hag in Kakariko Potion Shop, the next step in the trade quest.

Fate
Cojiro is not seen after Link returns him to the man. When Link returns later in the trade quest with the Odd Potion, he finds that the man has vanished and has apparently turned into a Stalfos. It would therefore seem likely that this Stalfos turned on and killed its old friend Cojiro, although this is never confirmed.