The United States Congress has passed a sweeping benefit reform bill that includes a provision to ban cockfighting in Pacific territories.
The practice of setting two roosters against each other in death matches is already banned in all 50 states, but Guam refuses to enact any such measures.
On the US-controlled island, cockfighting is closely tied to religious events and mainly held at village fiestas, with Guam law giving blanket approval for events on church holidays.
The ban is contained in a bill that requires low-income people to work 20-hours a week or enrol in education before they can apply for the federal food stamp programme.
In a statement, Guam's congresswoman Madelleine Bordallo says House Republicans have chosen to force a cockfighting ban on Guam against its will.
She says because US territories are not allowed to vote in Congress, the move is paternalistic and deeply unfair.
However, the bill is unlikely to pass in the Senate, where it needs 60 votes, with Democrats and some Republicans saying they will vote against it.