Poultry farmers could lose their licences if they keep more chickens than permitted after the Lunar New Year, a senior official said yesterday. Dr Liu Kwei-kin, deputy director of Agriculture, Fisheries and Conservation, said the department had tried to talk farmers into keeping fewer live chickens when it first detected overcrowding on farms in July and August. He said these farms had gradually increased stocks since resuming operations after the second bird flu outbreak last May. But the appeal was ignored and Dr Liu told a public forum yesterday the department had issued 22 warning letters to owners of overcrowded farms in October and November. No prosecutions have been brought. Overcrowding was detected on 15 per cent of Hong Kong's 146 poultry farms, he said. Dr Liu, who also appeared on a Metro Radio programme yesterday, refused to say if the six farms where the bird flu virus was found in the current outbreak were among those which had kept more than their permitted number of chickens. He also would not disclose whether the latest outbreak was related to overcrowding on farms, but said the overcrowded farms were in different areas. 'We are very much concerned about the situation. That's why we have immediately dealt with it,' he said. New licensing conditions brought in last month set a ceiling on the number of live chickens that can be kept, based on the size of poultry farms. From February 21, farmers who fail to comply with the new conditions are liable for a maximum penalty of loss of their licences. Dr Liu said the department had given farmers a grace period to sell existing stock and warned them not to keep more birds than permitted after the Lunar New Year. Ho Pak-leung, honorary secretary of the University of Hong Kong's centre of infection, said the latest bird flu outbreak had apparently been brought under control as there had been no new reported cases during the past 3.5 days. But he warned the virus could spread more seriously and spark an outbreak if it was found in a poultry farm which was overcrowded and with bad environmental hygiene.