Shelly,
 
Pam Grant is probably a better bet to give you all the details, but I know
that BY has a high concentration of B vitamins.  Also, the garlic repels
fleas (notice how I didn't say "eliminate"?).
 
All I know is that it's good for them and my ferrets have never had nicer
coats.  And our flea infestations have been cut in half or more!
 
Amy & Dave (and their gaggle of giggling ferrets)
RIP Ian and Elektra
[Posted in FML issue 1615]