A county society for the prevention of cruelty to animals may be formed in any county and a district society for the prevention of cruelty to animals may be formed in any group of two or more contiguous or noncontiguous counties or parts of counties by not less than seven incorporators. County and district societies shall be created as corporations under chapter 317A and as provided in the bylaws of the state federation. No county or district society may conduct investigations outside the boundaries of the county or counties included in the county or district society.