How loyal are Romney's NH supporters?

[porker]

By that, I mean how likely would they be to switch support to Huntsman in the case that he spends his personal wealth on attack ads and presents himself as a credible alternative?

[NHI]

I'd never vote for Huntsman in the primary, only in the general if it came down to it.

[CLARENCE 2015!]

Why do Huntsman and Romney hate each other? Huntsman goes after Romney all the time....you'd think they'd like each other being fellow Mormon ex-governors whose families are connected

[Mehmentum]

Why do Huntsman and Romney hate each other? Huntsman goes after Romney all the time....you'd think they'd like each other being fellow Mormon ex-governors whose families are connected

Ironically, they're similarities are why they hate each other, they're both competing for the same voters. 

[Dereich]

Why do Huntsman and Romney hate each other? Huntsman goes after Romney all the time....you'd think they'd like each other being fellow Mormon ex-governors whose families are connected

Because Huntsman and Romney are both going after the same constituency within the party, namely moderates and non tea partiers. EDIT: Ninja'd

As for the main question, I'd say that Romney's support is on a much firmer footing then, say, Cain's in South Carolina. He's got a favorite son effect, views in line with the state GOP's, and a frontrunner aura of invincibility propping up his poll numbers there. I wouldn't really expect votes to fall to Huntsman unless some big scandal brought Romney down. 

[Simfan34]

Why do Huntsman and Romney hate each other? Huntsman goes after Romney all the time....you'd think they'd like each other being fellow Mormon ex-governors whose families are connected

Ironically, they're similarities are why they hate each other, they're both competing for the same voters. 

I believe it's more personal, a family feud of sorts as they are related. For example, Romney and Huntsman wanted the Salt Lake Games Organizing Committee chairmanship, Romney got it while Huntsman didn't.

[NVGonzalez]

We stick just as well as Mitt Romney sticks with his positions.