Shares in chicken producer Tyson Foods soared on sharply higher profits, before fresh legal troubles sent them plummeting back down again.
Tyson, the largest US chicken processor, which is known for its pork and beef business, and the sale of prepared foods, issued an upbeat outlook for the rest of the year.
Shares surged initially, but in filing its results with the securities exchange commission, the company also revealed a subpoena from the US government, which it believes is related to a civil case for price fixing.
Share prices tumbled over 5% as the market absorbed the news, trading down 3.3% on the day in midday deals in New York, at $63.23.
"Due to our outstanding performance in beef and pork and strong market conditions in the first quarter, we are raising our annual earnings guidance to $4.90-5.05 per share," Tyson said.
This is up from up from Tyson's earlier forecast of $4.70 to $4.85.
Tyson's results were better than expected, with net income up 27% year-on-year, at $593m.
This left profits at $1.59 a share, beating analyst expectations of profits of $1.26 a share.
Tyson's revenues came in at $9.18bn, marginally up from last year's revenues of $9.15bn, beating expectations of $9.05bn.
"We're on a path toward what we expect to be our fifth straight year of record results."
The company expected domestic meat demand to rise in 2017, with exports also growing.
Tyson also forecast an increase in profits thanks to recent acquisitions, as well as an overhaul of the company's prepared food segment, to bear fruit it 2018.
But Tyson Foods said it received a subpoena from the US Securities and Exchange Commission on January 20.
The company said the request probably results from allegations that it has been involved in chicken pirce-fixing, "based upon the limited information we have".
Last year legal proceedings were launched against Tyson, among other companies, by US chicken buyers, who claimed a conspiracy to reduce production and drive up prices.
Tyson denies these allegations, and says it is cooperating with the Securities and Exchange Commission.
By William Clarke