ah, tsuwm, I spoke too soon. But still no rhaplu definition of "chook."

Even though I live on what Aussies would consider to be the wrong side of the Tasman, it seems to me that the word "chooks" here is being used in its most literal sense - chickens. The idea being that your small poultry will become aggressive two metre tall dunny-destroyers. Were any extant, the NZ equivalent might be "may your kiwi become moa." Just my $0.02

"Nationalism is an infantile disease, the measles of humanity" - Albert Einstein