Cal. Food & Agric. Code § 16905

It is unlawful for any officer, agent, or conductor of any railroad in this state, to confine any animals in cars for a longer period than 36 consecutive hours if the animals are being carried or transported by the railroad in carloads. At least every 36 hours the animals shall be unloaded for rest, water, and feeding, into properly equipped pens for a period of not less than five consecutive hours.