Amanda Hutton was jailed yesterday for the manslaughter of Hamzah Khan, whose decomposed body was found at her home two years after he died in December 2009.
As well as Hamzah's body, police found five children in "breathtakingly awful" conditions in her home.
Judge Roger Thomas heard Hutton's eldest son Tariq, given a two-year suspended jail sentence for preventing his brother's burial, told police Hutton had threatened to kill the other children if he talked.
He told probation officers his mother held a knife to the throat of one child two days after Hamzah's death and threatened to burn down the house.
Hutton, 43, was found guilty of manslaughter at Bradford Crown Court on Thursday. She admitted neglecting five of her other children, aged between five and 13, who were living in the terrible conditions.