Most of the poultry that die prematurely before slaughter on the mainland end up on the dining tables, a top ecologist has warned. Jiang Gaoming , a researcher at the Chinese Academy of Sciences' botany department, said in a report on the nation's poultry industry that mainlanders consumed 4.7 billion chickens a year. But at least 80 per cent of the poultry that died unexpectedly on farms were consumed, he added. He did not estimate the number of 'dead' chickens in the industry but said large poultry farms on the mainland housed 20,000 birds and every year an average of 1,000 would die. 'I have surveyed a number of northern provinces since 2005 and the results are chilling - 80 per cent of the dead birds end up in the human food chain,' Mr Jiang said on his blog. He said small factories, dumpling stalls and restaurants were often happy to buy the chickens because they were cheap, only costing around 50 fen/kg. Mr Jiang said the chickens were often roasted, used to make sausages and fed to other animals. He said battery farming, food additives and steroids fed to the birds accounted for the high death rate. To produce a mature chicken in 50 days, rather than the usual 200 days, farmers used sleeping medication, hormones and antibiotics, he said. Mr Jiang said the farmers readily admitted using such techniques, saying they were not going to eat the birds themselves but just sell them to the cities. He accused governments of failing to adequately supervise the poultry farms to prevent dead chickens from entering the food chain. Red tape made it difficult for farmers to get compensation for incinerated chickens during an outbreak of bird flu, prompting some to take the easier option of selling the dead poultry, he added. Poultry farmer Huang Jingtong , from Nanhai in Guangdong, said Mr Jiang's survey did not apply to the entire poultry industry. 'I admit many farmers feed chickens food additives, but I don't think the death rate is that high,' Mr Huang said. 'It's normal to raise chickens to maturity within two months in modern farming. It's not only China's farmers who do this.' Chen Junshi , from the Expert Advisory Committee on Food Safety, told Southern Weekend that dead chickens would not spread diseases if they were cooked at high temperatures, but farmers and vendors who traded in the poultry could be infected during the transactions.