London, Sep 30 An Indian-origin founder of Britain's 2 Sisters Food Group -- the largest supplier of chicken to supermarkets in the country -- is facing a parliamentary inquiry after an undercover investigation revealed poor hygiene standards and safety dates of chicken being allegedly manipulated in his factory. Ranjit Singh Boparan's 2 Sisters Food Group (2SFG), which owns the factory in West Bromwich, will be probed after a joint investigation by the Guardian and ITV News showed footage of workers altering the source and slaughter date of poultry being processed at the plant. Experts said their actions could artificially stretch the commercial life of the meat and dupe consumers into buying chicken past its use-by date. Other footage showed chicken being picked off the floor and being thrown back on to the production line, and older poultry being mixed with fresher birds. The empire created by 51-year-old Boparan, known as the "chicken king", employs 23,000 people. Neil Parish, the Chairman of Parliament's Environment, Food and Rural Affairs Committee, said he was preparing to call Boparan to Westminster to answer questions about the scandal. The Food Standards Agency (FSA) also launched an investigation into the company, which produces a third of all poultry products eaten in the UK. Three of the UK's biggest supermarket chains -- Marks & Spencer, Aldi and Lidl -- have meanwhile halted deliveries of chicken from the company's West Bromwich plant. Marks & Spencer said the footage showed "unacceptable" standards. All chicken received from the plant had been cleared from its shelves as a precautionary measure and all further deliveries had been stopped until M&S completed its own investigation of conditions in the chicken factory. Aldi and Lidl said they had also suspended supplies from the food processor, while Tesco and Sainsbury's had launched their own investigations. The prospect of the Boparan being called in front of parliamentarians emerged as the FSA said it had begun "liaising with the local authority in regards to taking the investigation forward and will consider whether offences have been committed". A spokesman for 2SFG said: "We have now had an opportunity to view all the evidence and launch our own internal investigation. This is ongoing and we will ensure our inquiries are comprehensive and thorough. We will of course continue to work closely with all stakeholders during this investigative phase." "2SFG ensures all staff are fully trained on hygiene and safety matters, and enforces a number of policies to ensure compliance with all regulations," the 2SFG spokesman said. Boparan founded the 2 Sisters Food Group in 1993 with a bank loan, and has since grown the firm into the UK's second largest food business by turnover. It claims to process around 6 million chickens a week. Boparan and his wife Baljinder Kaur Boparan are estimated by the Sunday Times Rich List to be worth 544 million pounds.