Pfizer ($PFE) has taken another big step forward in its long-term plan to whittle itself down to a completely pharma-focused endeavor. The corporate giant outlined plans to establish a $100 million IPO for its animal health unit, Zoetis. Pfizer will hand over shares of the company, covering about 20% of its value, to pay off debt. And then it will have a controlling interest that can be passed on to shareholders. The Big Pharma company says it plans to trigger the IPO in the first half of next year. Release