I agree with keesmom, I know of NO plants that would deter a hungry fox from luscious chicks or chickens!! I am advocating a very sturdy run AND electric fencing. I personally have a large enclosed space that is wired with electric fence...inside of which I have sturdy totally enclosed runs. We have fox, coyote, loose dogs, hawks, eagles, and owls. Never underestimate the winged predators. Another good reason for totally enclosed runs is the Avian Flu which is being NASTY this spring. We have had 6 confirmed cases in MN this spring, all on Turkey Farms. Keeping wild fowl away from your flock is a good bio security measure.