ZTS Board member Michael McCallister (Chairman of Humana's Board as well) just bought a block of stock. This is very good sign. He is very experienced and knows the business extremely well. Once the short term traders and HFs get out (and there are several of them selling here, like SAC, Tudor, and others) the stock is going to go on a relatively quick run to the high $30s. Buy the forced selling by these guys, this is your chance. Mark it down.
Your info is stale. In addition, insiders Heidi Chen and Stefan Weiskopf were buyers. Icing on the cake? SAC is just about done selling....expect the stock to lift big time over the next couple of weeks.