The youth services board may hold such meetings as are convenient and necessary, which shall be at least annually, to carry out its duties and responsibilities at such place or places within the state as it may direct. A quorum consisting of any nine members of the board shall be competent to act at all regular or special meetings. Special meetings may be called by the chairman of the board or by any three members of the board upon one week’s written notice to every member of the board, which notice shall state the purpose of the meeting.