Boy do I have a problem with this one too.  Sheena is almost 50 lbs and
should only be about 30.  This morning I found her chowing on Shadows food
(Shadow eats only one kind of food).
 
For rooms that the dogs don't need access to you can take a piece of
plexiglass and have it cut 1/4 inch wider than the door frame.  Depending
on how big/small your dog is would depend on how high you want it.  For
Sheena I can go with a 16 inch height.  Leave enough room below the
plexiglass for the ferrets to come and go easily and wedge the plexiglass
in the door frame.  Make sure it isn't placed too high that the dog can go
under.
 
My condolences to all that have lost their beloved fuzzies.
 
Hugs. tle
[Posted in FML issue 2419]