Typical window screens are useless!!! Hardware cloth, very well secured, must cover all openings. I've seen raccoons climb T-111 paneling easily, and so can many other predators.
My coop has recycled exterior doors from the Habitat Restore, with door locks, and the keys are hung nearby. No raccoon will get in that way!
Electric fencing is great when it's set up properly, with multiple strands of rope, wire, or tape, and on a good charger. Depending on how many weeds are against mine, it gives 8 to 10 joules according to my tester. It hurts!
Mary