When a fence between owners of improved lands is divided either by fence viewers or by the written agreement of the parties recorded in the town clerk's office where the land lies, the owners shall erect and support it accordingly. If any person lays that person's own lands common, and determines not to improve any part of them adjoining such fence, and gives 6 months' notice to all occupants of adjoining lands, that person shall not be required to maintain such fence while that person's land so lies common and unimproved. All partition fences divided by parol agreement and actually built in pursuance of such agreement, including fences so built heretofore, shall be deemed legal fences as if divided by fence viewers or written agreement, and the adjoining owners shall support their respective portions of fence under such agreement until otherwise ordered by the fence viewers on application to them by either party. When a party has constructed that party's part of a fence in pursuance of a parol or written agreement or assignment of fence viewers, no assignment may thereafter be made by fence viewers depriving that party of the full value of such fence or any part thereof.   [PL 1987, c. 737, Pt. A, §2 (NEW); PL 1987, c. 737, Pt. C, §106 (NEW); PL 1989, c. 6 (AMD); PL 1989, c. 9, §2 (AMD); PL 1989, c. 104, Pt. C, §§8, 10 (AMD).]