is there a good heart worm preventative for Ferrets? I was told by my vet to use revolution for ferrets and he said he called the company and they said to use 1/4 of tube for fleas but to use 1 full tube to prevent heart worm in ferrets. it is the Revolution for puppies and kittens less than 5 pounds kind. my ferret is 2 lb 5 oz. I thought that in using the whole tube he might get an overdose of the flea med that was in it just to get the heart worm protection. [Posted in FML 7117]