Translation

niwatori means "Chicken" in English.

niwatori written with kanji is 鶏.
This is a jouyou kanji 常用漢字, taught in junior high, chuugakkou 中学校.
niwatori written with katakana is ニワトリ.
niwatori written with hiragana is にわとり.
Romaji ni wa to ri
Hiraganaにわとり
Katakanaニワトリ
Kanji 鶏
School Level 中

Synonyms

Scientific name: Gallus gallus domesticus.

Further Reading

Wikipedia: ニワトリ (Chicken)