Dead magpie found after 1,000 chickens seized and mainlander arrested in raid on illegal slaughterhouse in Yuen Long A native bird found dead in a densely populated area is suspected to have had bird flu. Last night's announcement came after food authorities swooped on an illegal chicken slaughterhouse in Yuen Long, arresting its mainland operator and confiscating 1,000 live and slaughtered chickens. The common magpie was found dead in Dianthus Road, Shamshuipo on Thursday, and preliminary tests showed it was a suspected case of the H5 bird flu, the Agriculture, Fisheries and Conservation Department said. If confirmed as the deadly H5N1 flu, it will be the ninth such find since last month. Two infected backyard chickens, a songbird and five native birds have been found in Shataukok, Wong Tai Sin, Mongkok, Tuen Mun and Tai Po. The detection of H5N1 in several birds prompted the government to ban backyard poultry and sparked search-and-destroy operations against illegally kept birds. Food and Environmental Hygiene Department officers raided an illegal chicken slaughterhouse in Kai Pak Leng, Lau Fau Shan, yesterday after a tip-off. About 1,000 live chickens in metal cages were confiscated by agriculture staff. As with all poultry seized this week, they were put down and thrown in landfills. 'Since the birds did not show signs of sickness, we did not test them for H5N1,' a spokesman said. Eighty dressed birds were also seized and destroyed, as they were perishable, the department said. A man, believed to be a mainland overstayer who lived in the tin-and-wood shed, was assisting police last night. Operators of an unlicensed food factory face a $50,000 fine and six months' imprisonment. Villagers in Fung Kong at the foot of the Kai Pak Leng mountain range said they were not aware of the illegal slaughterhouse and did not know if there were any more in the area. A Mr Wu, who refused to give his full name, said: 'I had no idea until I saw the news on TV today. I think that if people are setting up illegal slaughterhouses in the area, then they would do so where it would be very hard to find.' On day five of the enforcement operation against backyard poultry, 200 agriculture officers in I 40 teams inspected 10,400 households. Illegally kept poultry has been found in the past two days at a farm, from which 329 chickens were seized, and from three other households, from which 16 chickens and four other banned birds were seized. The government has said Hong Kong must do all it can to stop bird flu to help global efforts against the spread of H5N1. Hong Kong is in the midst of the peak flu season and migratory birds that may carry H5N1 long distances usually fly from north to south in the spring, further increasing the risk of bird flu outbreaks.