It really depends on the cat. We have 4 (not counting the ferals). They are farm cats, and their job is to hunt. Two of the cats are savage hunters that catch anything from lizards and song birds to squirrels and moles. That said, none of my cats will mess with the chicks. When we got our chicks we raised the first batch in the house with the cats. The cats learned from the beginning that the chicks are family and not food. As the chicks grew older they started pecking at the cats' eyes, which reinforced that they were not to be hunted. When a dove comes in the yard and tries to eat the chicken food, the cats will go after it, but they won't touch a chick!