We've only got 1 roo, 8 hens, and 5 chicks.... and the 9 cats here have quickly learned that chickens "don't play fair!". Any time the cats have gone after the chicks, Mama AND the roo have given a lesson or two that they haven't forgotten. It only took a few days for all the cats to just ignore the chickens.
Our chickens graze all around the cats and dogs, being chased and chasing back. The cats, and especially the kittens, will still stalk the chicks, but haven't been stupid enough to "go for it", Lately. One of the TomCats thought he'd give it a try.... saw him go round the coop, following Mama and chicks..... about ten seconds later he comes flying back, Mama in hot pursuit! He didn't learn the first time, and turned around to try again.... this time, the Roo joined the defense team, and the TomCat didn't stop running till he was up on the porch and climbing the screen door!
The biggest threat to my chickens is the two Chihuahua egg-stealers that are the house dogs. They'll steal and eat an egg in a heartbeat!
Our chickens are in an 8x10 coop with a 10x10 chain-link dog run attached. They're let out every morning to "run" the acre here, and put themselves to bed about sundown. If I forget to close them up, they'll go in and out until dusk, then they're ready to call it a night.
We live along a major highway, with truck traffic, school busses, etc all day long. The first week we had them (got them as grown birds), they would wander close to the road, but the noise of the traffic would spook them back toward safety. I've never seen them get closer than 15-20 feet to either road (live on a corner).
Chickens Ain't Stupid! Wish I could say the same thing about all the kids
Kathy