In the lower court ruling behind US v. Park, the court recites various interpretive truisms:
The legal effect of an unambiguous written document must be decided by
the trial court as a question of law. If, however, the instrument of
conveyance is ambiguous, interpretation of the instrument is a matter
of fact for the trier of fact. Benninger v. Derifield, 142 Idaho
In interpreting and construing deeds of conveyance, the primary goal
is to seek and give effect to the real intention of the parties... If
the language of a deed is plain and unambiguous, the intention of the
parties must be ascertained from the deed itself and extrinsic
evidence is not admissible. Uncertainties should be treated as
ambiguities; such ambiguities are subject to being cleared up by
resort to the intention of the parties as gathered from the deed, from
the circumstances attending and leading up to its execution, from the
subject matter, and from the situation of the parties at the time
Neider v. Shaw, 138 Idaho 503.
The court then decides
The easement terms in question here are unambiguous. Clause 2(c)'s
term "general crop and livestock farming" cannot be reasonably
interpreted to include dog breeding, boarding, and training.
Regardless of how broadly one defines livestock farming, the Parks'
activities do not fall within its terms.
The support for this derives in part from Partello v. Stipa, 115 Idaho 522, where it is concluded that with respect to an agricultural exception to workman's comp, raising and sale of hunting dogs is not within the traditional definition of agriculture. Partello relies on legislative intent, which seems to run afoul of the Park district court thinking that it is unambiguous. The court notes this, saying
But it is equally clear that the legislature did not use the term in
its generic sense, so as to include the raising of all domestic
animals,. . . ."). The Government's citation to Idaho case law and
Idaho statutes referencing livestock and similar regulations, which do
not appear to include domestic dogs, further yield support for its
interpretation. The Parks argument that these cases and statutes are
limited to their particular legislative schemes or area of regulation
ignores the last words of Clause 2(c) which references "applicable
State and local regulations".
So since there is some statutory basis for concluding that dog raising is not livestock raising, and because of the end of clause 2(c), "the Court concludes that they provide persuasive support for the Government's interpretation of the easement" (but that support is not dispositive).
In the appeal, the court cited a case of an easement for "swimming and boating", which are not defined in the easement, which the Idaho Supreme Court found to be ambiguous (Mountainview Landowners Coop. Ass'n, 86 P.3d), relying on dictionary comparisons. The Park court then found similar uncertainty in the definition of "livestock", and indeed case law Levine v. Conner, 540 F.Supp.2d 1113 stating that
the scope of domestic animals used or raised on a farm can potentially
extend to guinea pigs, cats, dogs, fish, ants, and bees.
And yet, "we recognize that “livestock” has been used to describe a more limited set of animals such as cattle, horses, and pigs". Various competing statutory definitions of "livestock" are cited. The court also finds that "[t]he language in the easement does not provide us with any more clarity on the meaning of the term". Idaho statutory definitions are beside the point:
But, even though we apply Idaho law to interpret an instrument of
conveyance, see Benninger, 129 P.3d at 1238, it does not follow that
the definitions of the terms of the easement will be the same as the
definitions given in the Idaho Code.
And thus the court concludes that "livestock" is ambiguous, and summary judgment was premature.
There is no general solution to the problem of ambiguity of "livestock" under contractual interpretation; a court could rule that the term is unambiguous, or that it is ambiguous.
The Idaho shooting statute 25-2806 does not say whether dogs are livestock, though the government in the Park case presumed that dogs are excluded from the class "livestock" (though I don't see that: the statute is vague). The cases cited w.r.t. dogs as livestock are in different parts of the Idaho statutes, and there does not seem to be any case law that has discovered legislative intent behind this particular law. The only way to know for sure is assume that dogs are livestock, rely on 25-2806, and take your chances at trial (if it's not clear, that would be a bad thing to do).