New Jersey Statutes Title 4. Agriculture and Domestic Animals 4 § 20-7

Where the lands of any 2 or more persons shall join each other and 1 or more of them are using said lands for the pasturage or keeping of animals, each of them so using said lands shall make or amend and maintain a just proportion of the partition fence between said lands except when all of said persons shall choose to let their adjoining lands lie vacant and open, but no such adjoining owner shall be required to make, amend or maintain any portion of any such partition fence, unless he is using his adjoining lands for said purposes.