China has lifted a ban on US poultry and poultry products that has been in place since the December 2014 avian flu outbreak, opening the door to a potential $1 billion worth of exports from the US to China.

Major US chicken processors like Sanderson Farms, Tyson Foods and Pilgrim’s Pride saw their stock value climb to year highs on Thursday, following the announcement. US Trade Representative Robert Lighthizer called the development “great news for both America’s farmers and China’s consumers”, in a celebratory public statement. The US is the second largest poultry exporter in the world, behind Brazil, with more than $4.3 billion worth of product being exported last year, according to the Office of the US Trade Representative.

The ban being lifted marks a victory for President Donald Trump, who has faced heavy criticism from economists and US politicians for his trade war with China, which has included controversial tariffs.

At a weekly press conference on Thursday China’s Ministry of Commerce spokesperson Gao Feng said ongoing trade negotiations between the US and China can only continue if Trump rolls back his tariffs. Last month, Trump announced on Twitter that he is working on a “phase one” trade agreement with China that is “60%” done, but has made no promises about completely removing tariffs.