This is only relevant if you keep your ferrets outside. last year we had two fox attacks on our ferrets who are kept in an extremely strong home made pen anyway. the fox couldn't get into the pen but managed to pull Delilah and BB's hide legs through the chicken wire and literally ripped a leg off of each of them. both of them had to be put to sleep. i was absolutely devastated, but just thankful that the fox didn't get into the pen otherwise i would have none. a couple of months later after reinforcing the pen (at night there isn't any way of getting at the ferrets even through the bars we have basically massive solid metal and wood shutters that and impenetrable) a fox attacked again. we don't know how it managed to get hold of JJ's foot but it did. However, i'm happy to say that after some care JJ is well and doing well with only three legs. She actually gets around faster than the other 4. She climbs and plays just like any year old ferret. With the growing fox population and lack of food i warn anyone with their ferrets outside to reinforce any structures to prevent anything happening. or if you can bring them in at night, i had all of mine sleeping inside while we fixed the damage and reinforce everything. also if you have a dog let them mark around the pen, foxes tend to stay away from places dogs are.