Some states are “open range” or a “fence out” states, meaning that a livestock owner does not have a legal duty to prevent animals from getting onto the roadway. But some state legislatures have enacted statutes known as "stock laws" that modify the common law (rules contained in court opinions written by judges) and prohibit owners from allowing animals to run at large.
Oregon is a 'fence out' state, which traditionally means that livestock owners are not required to fence in their animals to prevent them from wandering onto others' property or public roadways. However, Oregon has modified this general rule through the enactment of 'stock laws' in certain areas. These laws require livestock owners to prevent their animals from running at large in specific districts where the law has been adopted by a vote of the residents. These districts are often referred to as 'stock districts.' In such districts, livestock owners must fence in their animals or otherwise be liable for damages caused by animals at large. Outside of these stock districts, the 'fence out' rule generally applies, and landowners must protect their property with fences if they wish to keep wandering livestock out.