(a) The term ``fur-bearing animals'' has reference to animals which bear fur of marketable value and includes, among other animals, rabbits, silver foxes, minks, squirrels, and muskrats. Animals whose fur lacks marketable value, such as albino and other rats, mice, guinea pigs, and hamsters, are not ``fur-bearing animals'' which within the meaning of section 3(f).
(b) The term ``raising'' of fur-bearing animals includes all those activities customarily performed in connection with breeding, feeding and caring for fur-bearing animals, including the treatment of disease. Such treatment of disease has reference only to disease of the animals being bred and does not refer to the use of such animals or their fur in experimenting with disease or treating diseases in others. The fact that muskrats or other fur-bearing animals are propagated in open water or marsh areas rather than in pens does not prevent the raising of such animals from constituting the ``raising of fur-bearing animals.'' Where wild fur-bearing animals propagate in their native habitat and are not raised as above described, the trapping or hunting of such animals and activities incidental thereto are not included within section 3(f).