Former Arkansas Gov. Mike Huckabee and former Massachusetts Gov. Mitt Romney enjoy an early advantage among likely Iowa caucus-goers, a poll of Iowa Republicans found Wednesday.

Huckabee would win the Iowa caucuses and Romney would place second, if caucuses including all the potential Republican presidential candidates in the contest were held today, according to a Neighborhood Research survey released Wednesday.

Romney and former House Speaker Newt Gingrich (Ga.), meanwhile, would have an edge in a narrower field of candidates, the poll found.

Twenty-one percent of likely caucus-goers said they would prefer Huckabee, followed by 14 percent for Romney, 9 percent for real estate mogul Donald Trump, 8 percent for Gingrich and 7 percent for former Alaska Gov. Sarah Palin, the poll found.

Twelve other candidates registered at 5 percent or below, and 24 percent of respondents were undecided in the first ballot test, which included every possible candidate.

But not all those candidates might run. Huckabee has flirted with a bid, but a number of indicators and quite a bit of insider speculation has suggested he ultimately might not run. Trump's and Palin's intentions are also an enigma.

In a second ballot test, excluding all three of those candidates, Romney was the benefactor.

Twenty-one percent would support Romney in the winnowed-down field, followed by 12 percent for Gingrich, 7 percent for Rep. Michele Bachmann (R-Minn.) and 6 percent for former Minnesota Gov. Tim Pawlenty.

Forty-one percent of voters in that scenario would be undecided.

The poll, conducted March 29-April 4, has a 5.5 percent margin of error.