James John Connors, 34, was sentenced to 15 years at a hearing in Luton Crown Court, while his wife and first cousin, Josie Connors, 31, received a four-year sentence, The Sun reported. The couple, along with Josie's father and one of her brothers, were convicted Wednesday.
Judge Michael Kay described the couple's actions as "pure evil." He compared the conditions under which the victims lived at a traveller camp in Leighton Buzzard, Bedfordshire, to a concentration camp.
"Their disdain for the dignity of others is shocking," Kay said. "They were not Good Samaritans but violent, cold, hard exploiters."
Tommy Connors Sr., 52, and his son Patrick, 20, were not sentenced Thursday.
The jury was unable to reach verdicts on three more Connors sons and on many of the charges involving the four who were convicted, The Guardian reported. The case was the first brought under a 2010 slavery law.
During the 13-week trial, prosecutors presented evidence the family recruited men, many of them alcoholics or addicts, promising them jobs with pay and good treatment. Instead, investigators said, they were kept in unheated sheds and forced into unpaid work.
The camp was raided in September after one man escaped. Police found 23 men living in squalid conditions.
Some of the men returned to the Connors family and refused to testify against them.
"They were controlled in such a way that in many cases they could not see it," Frances Oldham, the prosecuting lawyer, told the jury. "They became conditioned ... the reason for their exploitation was money. They may not in the strict sense have been slaves, members of the jury, but the prosecution say this: They were not free men."