Tyson Foods emerged last week as the winner of a bidding war for Hillshire Brands with an offer worth $8.55 billion, a record deal that drew mixed reactions from investors and analysts.

Tyson, the largest U.S. meat processor, raised its winning bid to $63 per share, topping a $55 bid from Pilgrim’s Pride, a subsidiary of Brazilian meatpacking giant JBS. Analysts said the bidding for Hillshire,...