California Code, Civil Code - CIV § 3341

1. In the prosecution of actions under the provisions of this chapter, it shall not be necessary for the plaintiff to show that the owner, possessor, or harborer of such dog or other animal, had knowledge of the fact that such dog or other animal would kill, wound or worry bovine animals, swine, horses, mules, burros, sheep, goats, or poultry.

2. Any person on finding any dog or dogs, or other animal, not on the premises of the owner or possessor of such dog or dogs, or other animal, worrying, wounding, or killing any bovine animals, swine, horses, mules, burros, sheep, angora or cashmere goats, may, at the time of finding such dog or dogs, or other animal, kill the same, and the owner or owners thereof shall sustain no action for damages against any person so killing such dog or dogs, or other animal.

Nothing in this section shall render an owner, possessor, or harborer of a dog liable for the accidental or unavoidable killing or injury of any bovine animal, swine, horse, mule, burro, sheep, angora goat, cashmere goat, or poultry which occurs in connection with or as an incident to the driving or herding the same from the premises of the owner, possessor, or harborer of the dog, whether such killing or injury occurs upon such premises or off of such premises.