A senior U.S. Department of Agriculture official confirms that as many as 20 million chickens may have eaten feed contaminated with melamine, the chemical added to protein shipments from China that has killed U.S. pets.
The chickens are still on U.S. farms in several states. The USDA has ordered the birds to be held out of the human food supply until testing can be completed to confirm suspicions that the birds actually ate any of the tainted feed.
USDA officials plan to work through the weekend and hope to have test results as early as Monday.
The official emphasized that even if the birds had eaten the feed, the USDA has "no evidence that this is a human health concern. … This is just about the animals."
Previously, there were only about 100,000 chickens on hold for suspicion of having been fed bad feed.
The USDA had also previously announced a smaller number of hogs and chickens were suspected of having eaten the tainted feed before they were slaughtered, processed and sold.