The county welfare board shall appoint, subject to the approval of the board of chosen freeholders, a director of welfare, who shall:
a. Be a citizen of this state and of the United States;b. Be able to read and write the English language;c. Be capable of making and keeping such records and reports as are lawfully required of him;d. Have complete knowledge of the laws concerning the relief and maintenance of the poor;e. Be in the judgment of the county welfare board a technically trained and qualified expert in the field of welfare service, with administrative experience therein; andf. Not be a member of the county welfare board. The county adjuster when qualified may be appointed for this office but when so appointed shall not serve as an ex-officio member of the county welfare board.