I am fortunate that I’m in a busy downtown neighborhood and I have 3 large dogs and an enclosed lot, so not many predators are brave enough. I do have the occasional raccoon, stray cat, hawk, and lots of opossums, but they seem to be more interested in the chicken food than the chickens as food...
I live near you in Santa Barbara and have been very successful with a 3-sided coop (although these past few weeks, I have hung tarps and plywood to enclose things a bit more, I have silkies that are a little more sensitive to cold and it's been cold!). I brooded in the house for the first week...