Cucco is a character found in The Minish Cap on top of Anju's Henhouse. For the majority of the game, Link is unable to reach the Cucco as Anju blocks the entrance to the main house while Spekter blocks the small Minish-sized entrance.
In order to reach the Cucco, Link first needs to reach the Royal Valley and meet with Spookter. After a second Kinstone fusion with Spookter, Spekter finally leaves his spot near the Henhouse. Link can then shrink down to Minish size and enter the house. Link can climb the fireplace to meet with the Cucco. The Cucco congratulates Link on making it over here. Link can then fuse Kinstones with the Cucco.