Cats are usually scared of chickens and will not bother them. Chickens are usually too big for a cat to tackle, however, there are certainly cases where cats have attacked and killed chicks, small bantams and very occasionally smaller hens (hybrid size) and even fully grown chickens.
Some cats are more interested in hunting than others but young chickens and smaller breeds are at the most risk. I have never had a problem with any cats in our neighbourhood, they sometimes stalk and watch the hens but when a hen comes towards them, they run off.
It is best to take precautions with young stock and cats, just in case… but with fully grown hens your best bet is to ‘test the water’ to see if you have any problems.
Have you had a cat attack your chickens? Please leave me a comment if you have. I would be interested in knowing what breed and size (bantam or large fowl) your chickens are too.