WASHINGTON (AP) — China is reopening its market to U.S. poultry, ending a five-year ban.

China had blocked U.S. poultry imports after an outbreak of avian influenza in December 2014, closing off a market that bought more than $500 million worth of American chicken, turkey and other poultry products in 2013.

U.S. Trade Representative Robert Lighthizer said Thursday that the U.S. welcomes the decision and predicted that U.S. poultry exports to China could surpass $1 billion a year.

The Chinese market looks especially promising for U.S. poultry producers because an outbreak of African swine fever has devastated a competing protein in China: pork.

Shares in major U.S. chicken processers, Sanderson Farms, Tyson Foods and Pilgrim’s Pride climbed to new highs for the year Thursday.