Allowing ferrets to mix with other animals requires rational thought as to the likelihood of injury either pet. Large animals can injure a ferret and a ferret will kill a  rabbit or similar pet.
   I remember when several ferrets escaped from their cage at a pet shop when closed; killing the rabbits,guinea pigs and  wrecking the the shop displays.  That is an extreme example. Ferrets are intelligent, good natured creatures when cared for correctly and treated with common sense.

Ferrets need to be watched!