(Bloomberg) -- Dairy farmers in California are grappling with a steadily advancing outbreak of avian flu in their herds – a problem few of them want to talk about publicly, but that none of them can afford to ignore.Most Read from BloombergThe Tartarian CandidateInside NYC’s Playbook for Getting Federal Grant FundsA Courtyard Apartment Building Designed for Southwest SprawlBooming Cambridge Exposes England’s Widening Wealth GapRobotaxis Are No Friend of Public TransportationBird flu has been rep