Yes, filing down the canines is a horrible thing to do to a ferret.  Those
ferrets will almost certainly require dental and/or medical care later in
their lives as they develop painful and life-threatening tooth and jawbone
infections.
 
If you talk to them nicely and they refuse to change their practice,
and if the local humane society or ferret-friendly vets can't convince
them to stop, then I'd say yes, a boycott is definitely in order.
 
Dennis
[Posted in FML issue 1201]