I had a ferret, then these pets weren't yet popular; I had many questions about how to take care of them correctly. I used cat food to feed my ferret and used cat litter for the ferret toilet. I searched for information on the Internet for a long time, for example, as in this article
https://bestferretguide.com/best-litter-for-ferrets/ and it helped me to choose the best option for me and my ferret. When my boyfriend gave me a kitten, I also used this cat litter for his toilet and despite the fact that the cat is larger than a ferret, this litter did a great job.