The poultry industry breathed a sigh of relief after three months of testing found two Northland egg layer farms free of infectious bursal disease.
The disease attacks the immune system. It does not affect humans, but is potentially lethal in chickens.
Bursal disease, avian influenza and Newcastle disease are the most feared diseases for the New Zealand industry, which last year produced more than 87.5 million chickens.
After an outbreak of bursal disease in 1999 the Poultry Industry Association introduced a sampling regime to test every farm at least once a year.
Association executive director Michael Brooks said one such test in March threw up a false negative, which raised the spectre of a new outbreak.
