Ah. That makes sense......Chook is an Australian slang word for chicken
Here in Aus it is also used as a term of endearment.
Mothers or Wives may be referred to as “the old chook” with no offence intended and simply a term of affection.
People who do something silly can also be referred to as “ya silly chook”, again, no offence intended.
It is also used in enquiring phrases such as “what’s up chook?” .. “what ya doin’ chook?”