Per Wisconsin State Statutes 174.042 1(a), 2, 3 & 4 – please read the following:
Dogs running at large and untagged dogs subject to impoundment; penalties.
(1) Dog running at large.
(a) Except as provided in par. (b), a dog is considered to be running at large if it is off the premises of its owner and not under the control of the owner or some other person.
(2) Untagged dog. A dog is considered to be untagged if a valid license tag is not attached to a collar which is kept on the dog whenever the dog is outdoors unless the dog is securely confined in a fenced area.
(3) Dog running at large or untagged dog subject to impoundment. An officer shall attempt to capture and restrain any dog running at large and any untagged dog.
(4) Penalties. If the owner of a dog negligently or otherwise permits the dog to run at large or be untagged, the owner shall forfeit not less than $25 nor more than $100 for the first offense and not less than $50 nor more than $200 for subsequent offenses.