Nairobi, Kenya (CNN) -- Eight-year-old Boku knows there is a trick to moving a goat from the market to the slaughterhouse. He knows you must grab behind both ears and pull. After two years on the job he has learned the hard way.
Mohammed Hassan, his five-year-old brother, hasn't quite got the knack of it yet. Still, they are thankful they have a job.
"Every day I wake up and go to the market to do my work," says Boku. "When I am finished I just come back home. I have to work, or we don't get food."
The brothers work in the chaotic and trash-strewn market of Kiamaiko, Nairobi. Adult traders finger through wads of cash and haggle over goat prices, around each trader the kids gather for work. But this is no place for a child.
Boku and Mohammed will earn less than one U.S. cent for each goat that they deliver up the hill to the Kiamaiko slaughterhouses. The market provides meat to restaurants across Nairobi, and it is awash with child labor.
The slaughterhouse owners, who wouldn't give their names for fear of arrest, told us that hundreds of children work inside their buildings cleaning entrails, collecting blood and mopping the floors.
As they pick their way through the slum between the market and the slaughterhouses, Boku and Mohammed are frequently robbed by older boys and harassed by kids going to school.
"I try to protect brother. He is so small and young," says Boku.
The brothers also face arrest.
Child labor is illegal in Kenya, but police rarely target business owners for hiring children in the slums. Community activists say the police get a cut of the thriving trade.
A senior police officer, who wouldn't give his name, denied this but said that arresting the market leadership is "complicated."
The police say they are doing their best to solve the problem, but that the numbers of kids working and the 'freelance' nature of their job makes its difficult for suitable law enforcement.
So in Kiamaiko they arrest the children. Each month the police will round up between 20 and 50 kids. Children who came from outlying areas are trucked out of the city, but they will almost always end up back at work, say the police.
The little money they can earn is a big draw. Most of the children work in Kiamaiko so their families to survive.
Boku and Mohammed's father died five years ago, and after their mother's shop burnt down, she became ill. So at six, Boku became the breadwinner, and soon his younger brother followed.
Their story is tragic, but by no means unique.
UNICEF estimates that one in five children in Kenya work. And poverty has forced millions of children across Africa to work.
In rural areas schooling can be adjusted to harvest time to ensure that children get an education. But in the urban slums of the Kenya, working kids often get no schooling at all.
Though Kenya has been lauded for introducing free primary education in 2003, according to the U.N. the majority of poor children in Kenya won't finish their first few years of school.
"They say it is free, but in other way it is not free because you have to provide a uniform, you have to buy books, every day when he wakes up you have to give him food and shelter," says Adan Roba, a community leader in Kiamaiko who is trying to convince parents to send their kids to school.
In Kiamaiko we found that many parents, especially mothers, actively push their children to work.
"They don't know about child labor, they think that everybody can work. But in a real sense child labor is not good for the community," says Roba.
I asked Boku what was his biggest dream. "To watch TV, to play with my friends and to go to school to become a teacher," he told me.
But as we watched Boku and Mohammed drag yet another goat through the alleyways of Kiamaiko those dreams seem far off.
Without an effective safety net for Kenya's urban poor, all Boku and Mohammed can really count on is a lifetime of work.