ferret cage behavior

Question
hi,
i have three ferrets. i have had them for four years. for those four years we have the same four story cage. they used to use only the bottom most part of the cage as a bathroom. however, a couple of months ago they began to use the entire cage as a bathroom. i have not changed anything about their life. thier idet is constatnt and they are let out everyday. i was wondering what could lead to such a problem and how can it be fixed.
sincerely
maya s

Answer
Hello Maya, and thank you for your question.
Many things can attribute to a ferret having this behavior, so it would be nearly impossible to decipher why they have all of a sudden started using a different part of the cage as their bathroom. The best thing to do is to go back to
"training" them to use either the litter pan, or the desired cage area.
  First,I am not sure if this will help, but if you are using a litter pan, I always used a DISH PAN. It is larger, and covers one whole side of the cage. I found the commercial litter pans to be too shallow, and are triangualr in shape, so that it leaves alot of room for "accidents".
Now,If your ferrets are pottying in a remote corner of the cage, (I.E. a corner that is too small for a litter pan) first, clean that area thoroughly to remove all scent,and
sometimes it helps to spray the area with vinegar (as a deterrent).Then put something IMMOBILE in that corner to BLOCK it,  i.e.: a play tube that's anchored to the side of the cage,  or an  anchored bowl or something so that they HAVE to potty somewhere else. A lot of times, if you give the ferret only so much room, and two of the accessible corners in the cage  are filled up by the litter pan (the dish pan is square so it stretches to both corners) then they will use it. Have them put some of THIER stool in the litter box, so they can detect the scent. After they become
re-acclimated to using the litter box, then increase their roaming room a little bit at a time, slowly removing the "anchored" objects. If you have still a lot of difficulty, and have exhausted EVERYTHING, you may have to get a smaller cage, so that the only room the ferret's have is the  bed area, food area  and the litter pan. It is the same as "crate training " a dog, and after they are 100% with the litter pan, them move them into the larger cage (the one you are using now).
ALSO< retrain them to use the litter pan (or potty area) every chance you get. For instance, if you are taking them out to play, and you notice them going up to the higher level to go potty, stop them, with a firm "NO" and put them down in the litter pan. And then you will have the "climb out, put them back" scenario for a few minutes, and then eventually, they will go potty, then BIG praise!!!! Eventually, with patience, they will "re-learn" to use the litter box.
I really hope this helps. I know this is a difficult situation. I myself had two ferrets who "reverted" in their litter training, and this method worked, but it took a couple of months of diligent, repetitive training.
Please let me know if this helps. Good luck, and feel free to ask any other questions.
amy