Freshly slaughtered chicken has been off the official menu in downtown Guangzhou for more than a year but Zhang combs the alleys looking for signs of black market poultry on offer. One signal could be a temporary boiler set up on a quiet side street.

“These mobile vendors are always on the move. They don’t stay in the same spot to avoid being caught,” Zhang said.

“Some operate from a van so they can drive away the moment inspectors turn up.”

Guangzhou introduced a five-year live poultry ban in 2015, with the restrictions applying to various downtown districts, including Yuexiu and parts of Haizhu, Tianhe, Baiyun and Liwan.

Under the ban, wet market vendors are only allowed to sell chilled chickens killed at a central slaughterhouse – a deeply unappetising prospect for the city’s “Lao Guang”, or long-time ­residents.

The poultry trade has also been banned at wet markets citywide for cleaning between the 16th and 18th days of January, February and March.

The aim of the bans is to contain the spread of bird flu. Since January, the H7N9 strain of the virus has killed at least 94 people across the country – the highest death toll since the first known case of human infection in 2013.

Most of the fatalities have been in the Pearl and Yangtze river delta areas.

In January alone, Guangdong reported 21 cases of H7N9, 10 of them fatal. That compares with 10 in the first two months of 2015 and 16 a year earlier.

Since January, human deaths and infections from H7N9 have been reported in 16 provinces and municipalities, according to the National Health and Family Planning Commission. Elsewhere in Asia, Taiwan, Japan and South Korea are battling bird flu outbreaks.

Analysts said the spike was probably partly caused by greater human exposure to infected poultry before and during the Lunar New Year festive season, with more people shopping for poultry, especially live birds. The H7N9 virus shows little or no clinical symptoms in poultry, complicating detection.

The spread of the strain has prompted authorities throughout the country to step up containment efforts going into the peak season for the virus.

Some Guangzhou wet markets, like the ones in Yuexiu district, have been banned from trading in poultry for the rest of this month. Live poultry markets have also been shut down in Zhejiang and various cities in Jiangsu. Parts of Guangdong, including Shenzhen, Zhuhai, Foshan, Dongguan and Zhongshan in the Pearl River Delta, have made similar prohibitions.

In some other high-risks areas such as Anhui province, where 23 deaths have been reported this winter, various cities and counties were ordered to restrict the live poultry trade.

Shanghai authorities have gone a step further by suspending the live poultry trade from January 28 until the end of April. Despite occasional reports suggesting the black market live poultry trade has been spotted in the city, the city’s health department reported only five cases of human infection last month.

But in Guangzhou, the fresh chicken black market is well and alive, with customers prepared to take the risk and pay around 60 yuan (HK$68) per kilogram for the illicit product. That compares to the 80 or so yuan more demanding customers will pay at the Wancongyuan wet market for the best chilled chicken processed by a slaughterhouse.

Zhang said she knew the black market was a health risk and tried to minimise her chances of contracting the virus. “It’s always dirty in the alleyways. Guts and feathers are scattered everywhere – you can’t expect much hygiene. We usually just point at the chicken we want and come back for it after the vendor was done processing it,” she said. “It’s OK as long as we don’t touch it.”

Zhang said she was not convinced that a sweeping ban on the live trade could ever be effectively implemented.

“Guangzhou, let alone the entire Guangdong province, is too big for a blanket ban,” she said.

“Guangzhou has been trying to sort out its rubbish problem for the past seven years and has failed miserably. They can’t ban live chickens.”