Central poultry slaughtering is being actively considered by health officials after it was revealed that most birds being sold have been exposed to the H9N2 virus. Officials have been unable to produce any concrete plans for central slaughtering, formally proposed by Coroner Paul Kelly at the bird flu inquest in June. Only the slaughtering of water birds has been centralised at Western market while people are still buying fresh chickens at retail markets where hygiene has been generally regarded as poor. Studies announced yesterday showed seven out of every 10 birds had been exposed to a new strain of bird flu virus, Influenza A H9N2. Department of Health community medicine consultant Dr Mak Kwok-hang said the Government was considering the proposal to improve public hygiene. 'We have to consider the response from the community where many believe freshly killed poultry are particularly delicious,' he said. 'Central slaughtering will inevitably change people's eating habits and customs. It will also affect the livelihoods of the workers in the poultry industry.' Dr Mak said that as the discharge from the mass slaughter of poultry would have an environmental impact, the Government had to carefully select the site of a central abattoir. Among the 521 consignments of local and imported birds tested, more than 70 per cent were exposed to H9N2.