Having sat through the relevant interviews, I want to say a couple of things:
1) Jan Mickelson is indeed the radio host who absolutely advocated slavery before. Specifically, he wants "illegals" to become property of the state in those words, so keep in mind that he's got a history of advocating actual slavery. And:
2) Mike Huckabee, despite what The Blaze said in their article attempting to cover for Mr. Huckabee (wherein they accused people talking about this of spreading a "horrific lie"), was absolutely not laughing off Mr. Mickelson's assertion that criminals should be made indentured servants. Mr. Mickelson has decided that prison is a "pagan" institution and concept, and is essentially trying to make slaves - or indentured servants, which is technically different but functionally not that much - out of people convicted of crimes. He really seems to be into the whole slavery thing, which I find quite disturbing.
Now, Mr. Huckabee did not use those "indentured servitude" words as Mr. Mickelson's did. He's not stupid enough to do that; he's a politician with a career, after all. But he was entirely supportive of the concepts.