COLUMBIA — Federal court documents show more than 20,000 roosters fought to the death at a South Carolina cockfighting ring over the past 18 years, a Columbia newspaper reported Wednesday.

“Every single bird in this case was treated with nothing short of extraordinary cruelty,” federal prosecutors wrote in the documents that surfaced Tuesday during a sentencing hearing for convicted cockfighting operator Jimmy Collins of Duncan, The State newspaper reported.

Fourteen fighting derbies were held each year in Swansea, about 20 miles south of Columbia, prosecutors said. More than 20,300 birds were killed during the 18 years of the cockfighting operation, with about 1,130 birds fighting to the death each year, prosecutors said.

Prosecutors had hoped the high number of rooster deaths would convince U.S. District Judge Cameron Currie to give Collins a stiff sentence. But the $5,000 fine and 21-month sentence were the lower end of possible time Collins could have gotten, the paper reported.

Currie also denied a request for leniency by Collins’ lawyer, who said his client is a law-abiding man who had worked with Clemson University animal scientists to eradicate chicken diseases. Wise also said Collins helped the FBI in its 2003 investigation of cockfighting probe that resulted in a guilty plea by former state Agriculture Secretary Charlie Sharpe.

Sharpe admitted in federal court he took $10,000 to protect a cockfighting organization from legal trouble and served time in prison.

Collins, who will remain free on bond while he appeals his conviction, was one of several dozen people rounded up last year and charged with cockfighting and gambling at Lexington and Williamsburg county contests attended by undercover agents.

Nineteen people have been sentenced so far, including 52-year-old Nancy Dyal of North, who was convicted in May of helping a cockfighting operation. On Tuesday, Currie sentenced Dyal to a year in prison.

Next Wednesday, Currie is slated to sentence 82-year-old Swansea cockfighting kingpin Gene Jeffcoat, who pleaded guilty earlier this year to conspiring to violate the Animal Welfare Act and federal gambling laws.