Well, I don't know too much about Europe outside of Norway. But in Norway there is Bear, Wolverine, Wolf, Lynx, Fox. But I guess only the Fox is a threat to the chickens, the other ones normally does not come that close, but I guess Wolf could get that close. Then we have Mink, and a smaller one that in Norwegian is called Røyskatt, it looks like a Mink, but just a lot smaller. They would be a threat to small chickens, but not a hen. But, they love a good meal of eggs. Then it is also hawks, and eagle too. I am from northern part of Norway, and does not know all about southern part of the country.
Fox and mink are natural in European nature. Raccoon was introduced in Germany during WW2 by Herman Goering and escaped later on. Skunk does not exist in Europe. Goshawk (Accipiter gentilis) exists.