N.H. Rev. Stat. Ann. § 466:19

Any person to whom or to whose property, including sheep, lambs, fowl, or other domestic creatures, damage may be occasioned by a dog not owned or kept by such person shall be entitled to recover damages from the person who owns, keeps, or possesses the dog, unless the damage was occasioned to a person who was engaged in the commission of a trespass or other tort. A parent or guardian shall be liable under this section if the owner or keeper of the dog is a minor.