I have 5 cats that all live in the house and while they watch the wild birds outside the window and make wierd little squeaky noises, they ignore my chicks. Not that I would trust them, but I think it has something to do with them growing up with birds living in cages, 2 parakeets. I even found my cats sleeping on top of the cage I was using as a brooder. Once the chickens are grown I think that my cats would be completly intimidated, but I have read about chickens being attacked by cats. It is just their instinct to chase birds, no matter the size. And I think that more the cats hunt, the more they will chase your birds. My cats have never hunted for a thing in their lives, accept for a place in the sun.