TORONTO -- The inquest into the starvation death of a five-year-old boy at the hands of his grandparents has heard from a foster parent who took in his three surviving siblings.

A coroner's inquest jury has heard about the "hierarchy" that existed among the children, with Jeffrey Baldwin and his six-year-old sister at the very bottom -- both referred to as "the pigs."

The foster parent, who became emotional during her testimony, told the inquest that the other two siblings were conditioned to treat Jeffrey and his sister as "sub-human."

The woman also recounted instances where Jeffrey's mistreated sister described the physical abuse she was subjected to by her grandparents, including being whacked with a broom.

When Jeffrey died of complications of chronic starvation in 2002, he weighed 21 pounds -- about the same as he did on his first birthday.

His grandparents -- Elva Bottineau and Norman Kidman -- had custody of Jeffrey and his three siblings despite both of them having previous convictions for child abuse.