The compensation of grand jurors shall be fixed by resolution of the board of county commissioners, not to exceed forty dollars for each day’s attendance, payable out of the county treasury. Except in counties of less than one hundred thousand population according to the last federal census, in which counties the judge of the court of common pleas shall make rules in the judge’s own county applicable to subsequent grand juror and petit juror service, a person who has served as a grand juror at a term of court is prohibited from serving again, either as a grand juror or petit juror, in that jury year in which the service is rendered or in the next jury year. The person is entitled to a certificate of excuse or postponement in the same manner as a petit juror. The court of common pleas may order the drawing of a special jury to sit at any time public business requires it.