If a county children services board is a public children services agency for a county, the board of county commissioners shall appoint five members of the county children services board and for good cause may remove any member so appointed. Each of these members shall be appointed for the term of four years, but the board shall stagger their terms so that the terms of not more than two of the required members of the board expire in one year. The elected chairperson of any citizens advisory committee established under section 5153.05 of the Revised Code shall be an ex officio voting member of the county children services board. In addition to the five members it is required to appoint, a board of county commissioners of a county having less than one hundred thousand population according to the last federal census may appoint up to five or a board of county commissioners of a county having a population of one hundred thousand or more according to such census may appoint up to nine additional members of the county children services board. If these additional members are appointed, they shall be appointed for initial terms of one, two, three or four years as will maintain balance in the expiration dates of the members of the board. After the expiration of these original terms, these additional members shall be appointed for four-year terms. Any vacancy shall be filled in the same manner as the original appointment.