Wells Fargo analyst Tim Evans downgraded Charles River Labs to Underperform, the firm's sell-rating equivalent, from Market Perform citing the recent rally in the stock. Evans thinks the market could be underestimating Charles River's exposure to research model demand, which he believes is likely in a long-term secular decline. He also thinks the stronger U.S. dollar will partially offset the improvement in preclinical growth, making a guidance increase from the company unlikely. Evans keeps a $70-$72 price target range for the stock, which closed yesterday up 82c to $78.67.