We have one big run with chickens, ducks and geese. When it was just the chickens and ducks, the cats (also big hunters although they bring in rabbits and squirrels as well as mice!) were very interested and paraded around the outside. When I let the chickens out to free range, I was always a bit worried about the cats but beyond the occasional little run at the chickens (I believe because they were amused by the clucking and scurrying, others believe they had other intents) they weren't fussed. Then we got the geese who soon sussed the cats as the enemy - the only time I've heard them hiss was at the cat. So now the cats tend to keep their distance. Ironically having worried about the cats and foxes, the only hen I've lost was to a dog (not mine)....
H