I find this article from The Holywood Reporter to be extremely frustrating and troubling:
Within a space of months, AMC has become embroiled in messy public fights with the creators of its top three shows -- Mad Men, Breaking Bad and now Walking Dead. The battles have been about money, but in this case, at least, it was more of a slow burn than a sudden flare-up. Sources say last fall, even before the first episode of the show had aired, AMC let it be known that it would effectively slash the show's second-season budget per episode by about $650,000, from $3.4 million to $2.75 million. AMC cut the budget and pocketed a tax credit previusly applied to the show.