A princess in the defunct Romanian monarchy has been sentenced to probation after apologising for her role in a cockfighting enterprise in the US, which she said had brought shame to her and her family.

“I’m very sorry about my involvement in this business,” Irina Walker told a federal judge. “It was not my intention to go against the law.”

She and her husband, John Walker, who live in Oregon, pleaded guilty in July to operating an illegal gambling business. John Walker, a former sheriff’s deputy, was also sentenced to probation by the US district judge Michael Mosman. As part of the plea deal the Walkers agreed to sell property and pay $200,000 to the government.

Irina Walker, 61, is the third daughter of the former Romanian king Michael I, who was forced to abdicate by communists in 1947. The judge agreed to let the pair travel overseas during their probation after their lawyers said the 93-year-old former monarch had health problems and his daughter wanted to visit him.

The Walkers were arrested in 2013 after authorities said they had staged at least 10 cockfighting derbies in a barn at their ranch. The pair charged spectators $20 to watch roosters with knives attached to their legs fight to the death. Crowds generally exceeded 100 people, and the couple also made money from the sale of alcohol.

Authorities said attendees paid $1,000 to enter the fights, and the prizes ranged from $10,000 to $18,000. The person whose birds won the most matches took home the money, except for 10% kept by referees.

More than a dozen people were charged over related offences.