Electric netting is very effective at keeping chickens in. Make sure you get poultry netting, as the netting is close enough to keep them from getting through. Recommend 4 feet tall. It does not keep out predators such as coyotes, foxes, hawks, and owls out.
It does keep out foxes. They were the primary reason I bought the fence. They won't come closer than 20' to it. They have had a taste of it, and didn't like it. My fence has been keeping them out for 4yrs.