Poultry workers in the US are dehydrating themselves and some have even taken to wearing nappies because of the slave-like conditions imposed on them by the country's biggest producers.

According to a report by Oxfam America, workers on production lines at Tyson Foods, Pilgrim’s, Perdue, and Sanderson Farms are routinely denied toilet breaks, jeopardising their health and leading to humiliating accidents.

At one Tyson plant in Arkansas, an older worker wet her pants in full view of her son, who also works on the line, prompting her to start wearing adult nappies on-shift.

Her story was echoed in the testimony of dozens of other workers, some of whom claimed they’d seen colleagues soil their trousers while on the line.

Some workers, who live in fear of being sacked if they complain, simply try and ensure they will not have to go to the toilet at all.

"You go to the bathroom one minute late, they have you disciplined," the Tyson employee, who works in Virginia, told Oxfam.

"The supervisor will have you sign a discipline paper…I don’t drink any water so I won’t have to go."

Troublingly, Tyson – the biggest poultry producer in the US with a market share of 23 per cent – is the only company among the big four that has a workers' "Bill of Rights".

While that charter does stipulate that employees are entitled to toilet breaks as required, it appears to have been ignored by floor bosses around the country – a fact that appears to have rung alarm bells with head office.

"(Tyson) does not tolerate the refusal of requests to use the restroom," the company told Bloomberg .

"(Management is) concerned about these anonymous claims, and while we currently have no evidence they’re true, are checking to make sure our position on restroom breaks is being followed and our team members’ needs are being met."

Similar statements were made by the other companies, including Perdue, which claimed its employees get two 30 minute breaks per eight hour shift.