They sure are! Chooks are a typical example of Australian colloquial language.
It’s an informal, everyday word, very much part of Australian farm and homestead culture. People might say things like:
“I’ve got a few chooks out the back.”
“Don’t forget to feed the chooks.”
“The chooks are laying well this week.”
Hahaha. I challenge you to use this term casually this week in your community 😉