Agriculture, provided that the keeping or raising of swine shall not be allowed as part of a general agricultural operation, and that not more than 10 head shall be allowed in any case, and provided, further, that no building or fence or other enclosure for the shelter of swine shall be closer than 200 feet to any property line or zone boundary and that no building, any part of which is closer to any lot line than 100 feet, shall be erected or used for the shelter of any livestock, fowl or other farm animals.