The Planning Board and the Town Council’s community and economic development committee will hold a joint public hearing Monday on eight proposed amendments to the town’s zoning ordinance. One would change the rules for locating bed and breakfasts, allowing them through special permit and under specified conditions in the downtown and some residential districts, while being prohibited in industrial districts, said Town Planner Greg Guimond. Another proposal would allow mixed uses downtown, where zoning rules currently permit only commercial uses. The proposal would allow housing on the upper floors of commercial buildings up to a maximum eight units per acre, according to Guimond. The hearing is scheduled to start at 7 p.m. at the senior center.