Victorian poultry farmers are dealing with the worst outbreak of avian influenza the state has ever seen, with concerns raised about the rapid rise of free-range farming.
Julie Kos's free-range egg farm at Stonehaven, west of Melbourne, is around 20 kilometres from infected farms and her birds have been forced to stay inside for the last six weeks.
"At first my heart sank to the ground when I found out; I mean, I pride ourselves on our birds being outside every day of the year," she said.
"They seem to be coping really well, like us humans with the coronavirus, you just need to get on with it."
It's the first time a housing order for poultry has been implemented in Australia. It is in place to stop wild birds coming into contact with domestic poultry.
"Commercial birds are more susceptible than wild birds, wild birds don't show any symptoms," Victoria's chief veterinary officer Graeme Cooke said.
"That susceptibility coupled with the way modern farming has large numbers of birds in one spot or one shed means that it spreads very quickly."
The housing order is in place until at least the end of September, but Dr Cooke said it could be extended.
"There's still a high level of virus in that area," he said.
"When we think the time is right — and it's constantly under review — we will lift that requirement."
Multiple outbreaks
The outbreak started at Lethbridge at the end of July and there are now six farms across the state infected with three different strains of the virus.
A free-range turkey farm at Bairnsdale in the state's east became infected after sick birds were transported from its sister farm at Lethbridge, about four-and-a-half hours away.
Farm manager Narelle Mollard said around 10,000 birds had been culled across the two farms.
"I cried, it was devastating," she said.
The farm has been undergoing the long and arduous process of decontamination.
"They [Agriculture Victoria] had a team of contractors come in to dispose of the turkeys, the litter, the mulch, the soil, anything that a bird could have come into contact with and it was all removed from the site," Ms Mollard said.
Rise of free range
Brian Ahmed from the Victorian Farmers Federation blames outbreaks like the one at Lethbridge on the rapid rise of large-scale free-range farming.
"This was not surprising to me, it's a numbers game," he said.
"The more we put outside, the more risk there is of something like this happening."
The worst-affected company, Farmpride, had to cull 380,000 birds, around a third of its flock.
"I think the consumer has in their mind where they see a few hundred chickens running around in this beautiful green grass and that's what they buy," Mr Ahmed said.
"Unfortunately, to produce the volume of eggs the supermarkets want, there needs to be 20, 30, 40,000 birds in a shed."
Frank Wong from the CSIRO said intensive chicken farms provided viruses like avian influenza with a high population of new hosts.
"There is a chance that the virus, if it mutates to a high pathogenic form, it becomes a serious disease and then it becomes very contagious," he said.
"Then we can sort of see the problems that we've seen in Lethbridge, where lots of chickens succumb to disease virtually over the course of a few days."
But for turkey farmer Narelle Mollard, it's a risk worth taking.
"It's opened my eyes, but if you want free-range turkeys as well as chickens or anything like that, it's a risk that you've got to be aware of," she said.
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