I had 5 chooks on my 750m2 yard block.
You just need to remember, and be prepared for the digging, and the poop.
They dig... they dig up your lawn until it turns to dust. They dig holes, as big as a dog would.

Now I have two chooks, find it much easier to handle. Also gives less eggs, which is good for us. With 5 we had soo many it was a joke. Even our neighbours were saying no, haha.

What are the fines if the council busts you? would it be worth it??