Pfizer Inc. (PFE) (PFE) is likely to divest its animal health unit through a combination of an initial public offering and an exchange of shares with current stockholders, Chief Executive Officer Ian Read said. “We’re probably going to exchange, part of it will be sold for stock in the open market, part of it will be swapped for Pfizer shares,” Read said today at the company’s annual investor meeting in Morristown, New Jersey. He said that no final decision has been made on how to shed the business.