Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you to remember:
A chicken is a newer 鳥 (にわとり). Well, it's a newer type of 鳥 compared to falcons and condors that have been around for ages. But chickens have only been around as long as us humans. Making them newer birds.
The chick I raised became a chicken.