The use of growth hormones is a contentious issue in the poultry industry internationally. The Poultry Industry Association of New Zealand states that hormones have never been used in poultry meat production, and that poultry is the only meat in New Zealand that is regularly and independently tested for the presence of hormones, and found free of them. Producers who label their chicken as having ‘no added hormones’ are simply stating industry policy, not differentiating their product.
Testing for hormones
Students in New South Wales, Australia, wanted to test the truth of the ‘no hormones’ statement. They raised two groups of chickens – one bred for meat, the other for eggs – and compared their weight after six weeks. The meat chickens were three times heavier – their genes were geared towards faster growth.
The fast growth-rate of meat chickens is due to advances in genetics and breeding, and New Zealand’s high standards of farming and nutrition – and not to the use of hormones.
Antibiotics have been used in meat, milk and egg production in New Zealand since government approval in the 1960s.
Antibiotics are routinely mixed into prepared feed or water to reduce the likelihood of intestinal infection. Their use has been questioned because routine exposure invariably produces resistant strains.
When high doses of antibiotics are used to control or treat disease, a withholding period is enforced to ensure no residue is left in the meat or eggs. The New Zealand Food Safety Authority regularly audits and tests antibiotic use and residues in marketed products.
Salmonella and Campylobacter cause gastroenteritis, which results in mild to severe diarrhoea, and in a few cases death. Although the heat of normal cooking kills both these organisms, care should be taken when handling eggs. In the 1990s the New Zealand poultry industry made efforts to reduce Salmonella levels in meat, and in 2009 it was present on 0.1% of carcasses (compared with 15–20% in the US). Salmonella bacteria was not found in New Zealand eggs, but was present on some shells.
In the early 2000s the poultry industry worked to reduce campylobacter prevalence on chicken meat. This resulted in a 60% drop in the monthly case rate over four years.
Cages were first used to protect hens from predators such as hawks, stoats and ferrets, and prevent birds pecking each other. Cages with automatic waste removal keep hygiene standards high, and minimise contact with wild birds which may carry disease.
Opponents of caging argue that the practice restricts hens’ movement and natural lifestyle, and causes health and behaviour problems. In the European Union battery cages have been phased out, and they will be banned in New Zealand from 2022. The New Zealand public increasingly prefers free-range eggs.
Removal of the point of the beak of newly hatched chickens is practised in all poultry farming systems to prevent feather pecking and cannibalism, which often occur when large numbers of birds are housed together. Modern beak tipping is done with an infrared beam that cauterises the very tip, where there is no nervous tissue. The part exposed to the beam drops off in one to four weeks. The earlier practice of beak tipping with a hot blade is very rarely used in New Zealand.
Opponents of this practice argue that it limits hens’ ability to forage and preen, and that reducing the numbers of hens kept together would prevent the problem.
New Zealand poultry is free from the three major bird diseases: Newcastle disease, infectious bursal disease and notifiable avian influenza. Birds in New Zealand do not need to be vaccinated against these diseases.
New Zealand poultry are unlikely to contract highly pathogenic notifiable avian influenza (bird flu), because the country is not on the flight path of migratory birds that spread the disease, and there are no imports of fresh or frozen poultry meat, eating eggs, or live poultry.