Hi Melinda,
 
Yes be very worried and concerned!  They will be using a Rodenticide that
will kill a ferret if it is eaten.  The Rodenticide always comes in some
form of edible material, they can not spray for mice.  The material could
be in block form, impregnated corn, etc.  More important is to ask what the
residual time.  It can be up to 2 months, in some favorable conditions.
The mice may disappear in 3-4 days, but the rodenticide will still be
there.  If you have any visible openings, you can use the metal circles
from an open can of veggies, etc., you can also by heavy duty steel wool
and stuff tightly in holes.  Please go thru your home at the level of your
fuzzies and close every opening.  When you think you may have covered them
all, your fuzzy will find one.
 
Dooks
[Posted in FML issue 2671]