According to a Franklin Pierce University/Boston Herald poll, Bernie Sanders has taken a lead among Democrats in New Hampshire. The poll, which was conducted between August 7 & 10, has Sanders at 44% to 37% for the former Secretary of State. The margin of error is +/- 4.7%.
The argument could be made that the poll is an aberration. After all, Hillary is still leading by a substantial margin in all other polls and this poll had a relatively small sample size - 442 likely Democratic Primary voters to be exact. Sanders is also not an unknown quantity in New Hampshire as he represents the neighboring Vermont.