An health officer packs dead chickens at a wholesale poultry market in Hong Kong January 28, 2014. Hong Kong began culling 20,000 chickens and suspended imports of fresh poultry from mainland China for 21 days on Tuesday after the discovery of the H7N9 bird flu virus in a batch of live chicken from the southern province of Guangdong. REUTERS/Tyrone Siu (CHINA - Tags: ANIMALS ENVIRONMENT HEALTH SCIENCE TECHNOLOGY)