Can ferrets eat raw chicken

They certainly would do, given a chance - if you have a caged bird, it'd be a good idea to keep a ferret away from it because birds fit easily into the category of things ferrets instinctively hunt.

In the wild, polecats (ferrets' ancestors) will eat birds occasionally but they don't form a large part of the animal's diet because birds have much better eyesight than ferrets and will fly away before the ferret is even aware there's a bird nearby. However, they do occasionally get into chicken sheds and will also kill and eat game birds confined to pens.