"A number of studies have found that carbon dioxide gas causes the birds to suffer before they die," director Debra Probert said in statement released Friday morning.
"There is significant scientific opinion indicating that poultry experience difficulty breathing and respiratory distress when gassed with carbon dioxide."
Probert is calling on the Canadian Food Inspection Agency to look into other gas mixtures already in use in Europe for culls during disease outbreaks.
She said the European Food Safety Authority, for example, recommends using inert gases such as argon or nitrogen or a mixture with no more than 30 per cent carbon dioxide.
Probert said she asked the CFIA to make the change after the last avian flu outbreak in 2004.
"I feel like as a progressive society that we have an obligation to make sure these birds have a humane death and I would like the CFIA to look into it and to report back on why they aren't doing it."
The B.C. government has been using carbon dioxide to cull inflected poultry flocks during avian flu outbreaks for several years, including the most recent outbreak affecting at least 10 farms in the Fraser Valley, east of Vancouver.
The birds are killed by sealing up the barns and flooding them with carbon dioxide, a process which is monitored by the B.C. Society for Prevention of Cruelty to Animals.
Afterwards the birds bodies, bedding and feed are composted together in the barns for about a week to prevent the virus from spreading and then, after the compost is removed, the barns are disinfected.
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