Deng Pioth Yai, local chief:
"In my area of 5,800 households, 300 children were abducted - 50 have returned.
This has really affected the region. The parents have now grown old and the children should be looking after them.
You can often see the parents getting drunk in the market. They have lost hope and self-respect."
Interviews: Joseph Winter, photos: Emma Lynch
Modern slavery: Special report