Diatomaceous Earth. All the animals on the ranch love it. The horses actually lick it off the bottom of their big food tub. It should be good for removing parasites and heavy metals.

This cute friendly cat that comes around seems like she had some worms because she was pretty thin so I started mixing some D.Earth in some fresh goats milk and she likes it as well.

http://wolfcreekranch1.tripod.com/defaq.html