Conflicts between persons engaged in animal husbandry and their neighbors have given legislative bodies many challenges in responding to competing equities. One set of rules has concerned the enclosure of domestic livestock, and legislative bodies have adopted assorted fence rules to resolve competing interests associated with grazing by domestic animals. Alternative fence-out legislation still exists in some jurisdictions for open range and very rural areas. Under fence-out legislation, ranchers do not have to build fences to confine their animals; rather, persons who want to keep out stray livestock have the burden of putting up a fence. Economists have given considerable attention to the externalities posed by livestock and the economic consequences of fence-in and fence-out rules, but have not considered the entire spectrum of scientific knowledge regarding the selection of a preferred rule. This paper addresses recent agro-research strategies and the comparison of property versus liability rule protection.