Two factors are at work here

Over the longer term the Chinese pork herd is decimated by swine flu. It will take years to recover. So it is strongly expected that substitution to chicken will lead to stronger chicken volume and pricing. However over the near term the US corn crop looks very poor right now due to poor planting conditions. The fear is that feed prices will rise.
The reports I've read suggest substitution to chicken will have a far greater impact on prices than feed costs will.