In 2004, the workers organized the League and voted to be represented by it.
In 2005, the League negotiated with Foster Farms. The League proposed a union shop contract with substantial pay increases; Foster Farms proposed an open shop contract with nominal pay increases. The League affiliated with the International Association of Machinists. Foster Farms refused to recognize the League's affiliation with the IAM. A three-day strike occurred in October 2005.
In 2006, Foster Farms and the League agreed to an open shop contract with nominal pay increases. The League's members ratified the contract on October 29, 2006.