Shares were slipping 30 cents, or 2%, to $14.75 early Monday.
For the fourth quarter ended Sept. 29, Tyson earned $32 million, or 9 cents a share, reversing a prior-year loss of $56 million, or 15 cents a share. Analysts had an average estimate for earnings of 10 cents a share, according to Thomson Financial.
Sales rose to $6.88 billion from $6.47 billion the prior year, exceeding Wall Street's estimate of $6.73 billion.
Tyson said, however, that it is experiencing "challenging" market conditions. It forecast earnings of 30 cents to 70 cents a share for fiscal 2008, well below analysts' average forecast of $1.02.
"Based on present assessments, we believe we will incur additional increased grain costs of approximately $300 million in the chicken segment,'' said President and Chief Executive Richard Bond. "The current beef environment is extremely difficult as well."
In the fourth quarter, volume declined 3.3% in Tyson's chicken segment and fell 0.3% in the beef segment, but price increases helped lift revenue. Pork volumes were up 7.1%, though average prices fell 1.9%.