"Uma Chicken!" is an episode of Oobi from the first season.
Oobi, Kako, and Uma play Old MacDonald and pretend to be farm animals. Uma won't stop pretending to be a chicken until she finally comes face to face with a real live chicken. She decides she would rather be Uma after all. — ABC Television
Oobi, Uma, and Kako are in the backyard listening to "Old MacDonald Had a Farm" on their tape player, singing along with the viewers. Oobi gets the idea to play pretend animals. Oobi dresses as a sheep and Kako dresses as a pig. Uma decides that she wants to be a chicken. At first, she confuses a chicken with a dog and barks. Oobi whispers something into her ear and she begins clucking like a chicken.
Grampu calls the children inside for lunch. Although Oobi called the end of the game, Uma continues to act like a chicken. Uma refuses to eat the sandwich Grampu has prepared for her, despite how she normally loves peanut butter and jelly. Grampu decides to play along with her game and gives her a bowl of sunflower seeds, telling her that's what chickens eat. She eats it excitedly, but ends up disliking the taste of the seeds. Grampu gives her her sandwich back, which she decides to peck at.
Later, Oobi and Kako play catch with a baseball and are interrupted by Uma. They tell her that they are playing a new game and ask if she wants to join. She declines and sits on the ball instead. She gets up, claiming that she laid an egg. She hands the ball to Oobi claiming it to be a gift, but Oobi and Kako, obviously disgusted, only handle the ball using the tips of their fingers and groan in disgust at the ball. The boys ask her to play hide-and-seek and she declines their offer again.
Kako suggests duck-duck-goose, but Uma says she wants to play chicken-chicken-chicken. The boys decide there's no hope and leave her to play chicken. Uma hears a chicken cluck and finds an actual chicken in the yard. She asks to play hide and seek with it, but it doesn't respond. She asks it to lay an egg, but again, it gives no response. She decides that chickens are not as interesting as she thought and stops playing chicken.
Oobi and Kako are playing tag in the field when Uma appears. She tells them that she is not pretending to be a chicken anymore. She joins their game and asks the viewer to join them, tagging the viewer as "it." An interview segment begins, where Kako asks the viewers if they like to play pretend. Afterwards, Oobi gets the idea to play a guess game with Uma. He gradually draws a chicken and asks Uma to guess what it is. Grampu walks in with a chicken costume and pretends to peck at Uma as the episode ends.