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.
Colorado is considered a 'fence out' state, which traditionally means that landowners have a responsibility to fence out livestock from their property if they wish to keep them off. However, Colorado law has evolved to include 'stock laws' in certain areas that require livestock owners to prevent their animals from running at large, including on roadways. These laws vary by county and are not uniform across the state. In 'open range' areas without such stock laws, a motorist who hits livestock may be responsible for the damage to the livestock as well as to their vehicle. Conversely, in areas with stock laws, the livestock owner may be liable for damages caused by their animals being at large. It is important for livestock owners to be aware of the local regulations in their specific county to understand their responsibilities and potential liability.