WASHINGTON (AP) — Republicans and Democrats are joining together to demand changes to the nation's farm worker program as Congress looks to rework U.S. immigration laws.

Lawmakers and witnesses at a House Judiciary subcommittee hearing Tuesday said the visa program that allows farmers to hire foreign workers is so unwieldy it accounts for only a very small percentage of the hundreds of thousands of farm workers hired in the U.S. And half or more of agriculture workers are here illegally, experts agree.

These workers play a critical role to the U.S. economy and food supply. But farmers and growers say their productivity and ability to keep operations in the U.S. is threatened by difficulties ensuring a stable labor supply, and that must change. Meanwhile workers said they should get more protections.