It’s illegal to leave a fence open, you could face a $750 fine for doing so.
With recent events surrounding the James Kim disappearance and rescue operation in neighboring state Oregon, this law sort of makes sense.
6-9-202. Neglect to close fences; penalty.
A person is guilty of a misdemeanor punishable by a fine of not more than seven hundred fifty dollars ($750.00) if he opens and neglects to close a gate or replace bars in a fence which crosses a private road or a river, stream or ditch.