H7N9 bird flu
A New Taipei City Department of Environmental Protection worker sprays sterilizing anti-H7N9 virus disinfectant around chicken stalls in one of the city's markets on April 8, 2013. Reuters

McDonald’s Corporation (NYSE:MCD) is slashing chicken McNugget prices at its Shanghai, China, restaurants amid rising concerns that the bird flu outbreak may have compromised the safety of the city's poultry market.

While the fast-food chain had previously sold a McNugget meal for 36 yuan ($5.80), the popular meal is now selling for 20 yuan ($3.22), nearly half its original price.

The McNugget discount comes just days after Shanghai’s live poultry markets were shut down on Saturday after authorities banned trading in birds to prevent the spread of H7N9 bird flu, which has killed six people in China.

Shanghai has reportedly claimed six of the country's 16 confirmed cases of the H7N9 strain, found in humans for the first time, with four deaths. The other two fatalities were in the neighboring province of Zhejiang.

McDonald’s has yet to comment on the reason for the McNugget markdown, but it is most likely a marketing scheme to clean out its current chicken inventory.

Shanghai had removed more than 20,500 birds at an agricultural market in a western suburb by Friday, after the virus was found in pigeons, and the government announced a ban on live poultry trading and markets.

Reports indicate that eggs, including pigeon eggs, remained on sale, as well as fresh and frozen poultry meat, with officials encouraging people to cook them well.

In related news, prices of vegetables and seafood have surged since the ban was announced at a government news conference on Friday afternoon, local television reported.

There was no evidence of human-to-human transmission in Shanghai, city officials said.