Raccoons can, and will shred chicken wire. If you do use chicken wire, don't leave your birds in the run overnight. Be sure to lock them in a secure coop. Rats can also get through chicken wire and will eat young chickens if given the opportunity.
X 2 - as for the predators you have, you'd be amazed at the animals that live around you that you are entirely unaware of. Not seeing a species does not mean the species is not there.