The California Department of Fish and Wildlife has published a summary of regulations and recommendations regarding monarch butterflies in various regions of California. The document covers many topics including regulations governing the handling of monarchs, captive breeding, and recommendations concerning planting of milkweed and other plants to support monarchs. The recommendations were developed in collaboration with state and federal agencies as well as several non-profit organizations focused on monarch conservation. The complete document can be found at this link: CDFW Monarch FAQ August 2021