Gu-Gu Ganmo

(from ebookjapan):

He is a chicken, but not a chicken, and although he understands human language, he is not a human. Ganmo is a chicken-like housemate who has fallen in love with an ordinary family.

He is currently struggling to become a good pet for his owners, Hanpeita-kun, a mischievous third grader in elementary school, and Tsukune-chan, a carefree junior high school student! How will Ganmo do?