Older Ferret

Question
My, now, oldest was given to me as a gift. I was told that she was alone on one side of the cage while the others stayed away from her; even the store clerk was afraid of her. She was difficult at first (biting and drawing blood with her baby teeth each time I picked her up). She grew out of it but was obviously jealous whenever I gave the other two, whom I had before her, attention.

She is now 8 years old and the other two have passed away. Two younger ferrets (ages 1 and 2) have entered her world. She has lunged at them both when trying to introduce them. One time, she missed the 2 year old boy and latched on to the friend who was holding him; she has been apologetic to my friend ever since for her mistake even though she didn't break skin.  She has freaked out the 2 year old ferret so much during a couple of attempts at introduction or just letting them "fight it out" that I decided to stop trying.  As a result, I keep them in separate cages and alternate their play times.

Additionally, the oldest has gotten to the point where she does not want to back into the potties like she used to. I've resorted to puppy pads to avoid messes when at work or overnight as she's allowed to stay out of the cage during those times; the other two get into too much mischief when they are out unsupervised. Her medical conditions are: cancer (surgery at age 5... not all was able to be removed), receives a monthly lupron injection to slow the cancer's growth, eye cataracts, she is on c-prednisone given her last checked blood sugar level, and she has recently had three major teeth removed which may have been causing her pain.

I have a few questions: why might she not want to use the litter pans like she used to? Is there something I need to do differently? ... Should I try to introduce them or continue keeping them separate? If you think I should try to introduce them, how would you recommend it (I'm very afraid she will seriously hurt one of them or that the "introduction" will be traumatic for one of the younger ones)?

Answer
I am usually all for introducing ferrets, but yours is 8 and that is very old for a ferret.  I am sure sh is set in her ways and probably feeling pretty icky from cancer, cataracts, and tooth problems.  I wouldn't try to add any stress to her at this age.  Additionally, she is probably not completely in control of her bladder or unable to get to the litter box in time or even unable to climb into it.  Things get harder as we age (humans included) so I would just be happy with her as is and not worry about her potty habits or her being alone right now.  Make sure to give her lots of places to be warm and lots of attention.