Welcome! While fox, raccoons, coyotes, and many other predators are
primarily nocturnal, but they are not strictly so. I've had a hen killed in the middle of the day by a raccoon and I've had several chickens taken at once in the middle of the day by a coyote. Especially in spring and summer when they have young ones to feed. I free range, but it comes with a price. Before the coyote attack, I went for 3 years of free ranging without any trouble. Another thing to consider is that just because you've never seen a fox during the day, it doesn't mean they're not there. Most wild animals prefer to avoid human contact. It's surprising what you will see once you have chickens.