I'd have to disagree with you there. I've been free ranging chickens for 40 yrs now and not just a few....large to medium flocks. All that time I've also had cats and never once has a cat attacked a chick or chicken. One set of half grown kittens was stalking one set of chicks and all I had to do was correct them, much as I would a dog, and that was the end of it. In fact, one of those kittens was killed on the highway but the other lived with us many years and I could call him to round up the adult chickens for me that had gotten out of the fence. He would round them up and chase them back over the gate, then lay down and look at me like he just had the best fun in the world. It's all about what kind of relationship you have with your cats and dogs that dictates how they react to what is yours.
Now, having said that, I wouldn't trust a strange, stray cat around the chicks at all and have had feral cats attempt to stalk adult chickens, even, but the dog soon put an end to that.
Didn't know there was a thread on free ranging or I would have posted sooner. I've been doing it for 40 yrs now and wouldn't keep chickens any other way. Minimal predator loss in all that time until this spring, when I lost newly hatched 20 chicks from 4 different broody hatches to black snakes....but all those chicks were inside shelter at the time of predation, so free ranging didn't have a thing to do with it, a black snake can get into any building it wants and the dogs will not hear it, see it or smell it doing so.
I've got some fine bird netting to place around the coop....snakes seem to get all tangled up in that stuff, which I found out by accident once, so now I'm going to use that knowledge to try and prevent it from happening next spring.