Wisconsin’s exemption for small farms is one of many federal and state carve-outs that have historically left farm workers — and dairy workers in particular — with fewer rights and protections than others.

For most workers in Wisconsin who get hurt on the job, the state’s workers’ compensation system is there to cover medical expenses and pay a portion of their wages while they heal.

“One of the bedrock principles of worker’s compensation is universal coverage,” the state’s Department of Workforce Development, which oversees the workers’ compensation system, says on its website. “That means that virtually every employee is covered.”

But the law is different for farms, and many immigrant dairy workers — the backbone of one of the state’s most celebrated yet dangerous industries — don’t get this protection. Wisconsin exempts all kinds of farms with fewer than six employees not related to the owners from the requirement to have workers’ compensation coverage.

No state or federal agency appears to track how many of Wisconsin’s 5,700 or so dairy farms fall into that category — or how many workers go without coverage. Neither does the Wisconsin Farm Bureau Federation, one of the state’s most powerful lobbying groups.