Workers in plants run by the largest US poultry producers are regularly being denied bathroom breaks and as a result some are reduced to wearing diapers while working on the processing line, Oxfam America has reported.

US stocks sank amid increasing pessimism on Wall Street today, shedding early gains after oil prices reached another record high and a mix of data provided conflicting views on the economy.

A gunman walked into a Texan chicken processing plant and shot dead a company official before killing himself.