We humans have the big C (cancer). Ferrets actually have the Big 3 - Adrenal Disease (AD), Lymphoma and Insulinoma. AD is mostly treatable with medications or surgery. Lymphoma and insulinoma are certain death sentances. Sometimes the tumors can be removed and medication can help but they are quick killers.
Hog was a great little ferret with a lot of problems. A Royal Canadian Farms bred ferret who escaped without his medical conditions being caught - yeah for him - sad for his purchaser. He was a runt, had a bad heart (easily heard by his lung and snorting) along with signs of other health problems. He was just about 2.5 years old when we met. Then just last week he collapsed. He has always been unstable on his rear legs (clear sign of insulinoma or lymphoma) but this time he couldn't control his front legs. His huge front paws stayed curled as he tried to walk. His little pig eyes looked at you like - why can't I move? To the vet he goes. We decide to try prednisone just to see if we can get him to be able to move on his own. He was unable to. We had to let him go. To let you know, the final death by either lymphoma or insulinoma is painful to the ferret. At least that is what I have seen. The tumors can suddenly become painful in their growth. We have seen tumors appear overnight. Or grow to the size of a golf ball in just a couple months.
Factory farms have created what I see is the Big L I (lie). They produce hundreds of little sweathearts with short lives. Average lifespan is 8 years old. But by age 5 is where you start seeing the Big 3 come around. Sometimes you will be very lucky and never see these. Sometimes it will just be Adrenal Disease and treatable. Sometimes not.
Just research where your furkids come from. Even with the bad, I love my furkids. They are the only animal I want to own now. Even with the heartbreak.