A structure designed and constructed to house farm implements, hay, grain, poultry, livestock or other horticultural products.  This structure shall not be a place of employment where agricultural products are processed, treated or packaged, nor shall it be a place used by the public.  The sole purpose of the building must be agricultural.  Excluded from the definition of agricultural building are structures enclosing an indoor riding arena with an occupancy load of 10 or more.