The notion that animals should have rights was widely ridiculed when it was first advocated in the 1970s. Now it is getting more respect. The movement has gained tens of millions of adherents and has already persuaded the European Union to require that all hens have room to stretch their wings, perch and lay their eggs in a nest box, and to phase out keeping pigs and veal calves in individual crates too narrow for them to walk or turn around. And earlier this month Californians voted 63 percent to 37 percent for a measure that, beginning in 2015, gives all farm animals the right to stand up, lie down, turn around and fully extend their limbs. The state's 45 major egg producers will have to rip out the cages that now hold 19 million hens, and either put in new and larger cages with fewer birds or, more likely, keep the birds on the floor in large sheds. California's sole large-scale pig-factory farm...