Well, since San Diego County is warned that we may get "measureable precipitation" this weekend, I would certainly hope that your flock has someplace to be during the rain.
Here in my part of SD county we have seen foxes, coyote, raccoons, rodents of every description, possum, garter snakes, possum, and hawks. I don't know where you are in SD county, but I am 15 minutes from down town, if I still lived in Jamul there would be more preditors than we have here. Oops, forgot to mention neighborhood dogs and cats.
I feel secure from many of these because the Delightful Dozen are surrounded by a 6 foot fence, but at night they are in a solid built coop which is in a secure run, all of which is in the yard with 6 foot fences. My neighbor behind me lost both of her hens to raccoons because they were not locked up at night.
Best of luck with your girls - where in the county are you?