Years ago, legendary activist Cesar Chavez helped create the first health insurance plan for farmworkers who toiled for meager wages in California’s fields. The plan, funded by the workers and their employers, is named after Democratic icon Robert F. Kennedy, who allied himself with Chavez. But like many other insurance plans around the country, it doesn’t fully meet requirements set by President Obama’s healthcare law. Unless supplemental insurance is purchased, the farmworkers say, 10,700 people could lose coverage.