Alleged undercover footage of a UK hatchery, filmed by vegetarian organisation Viva!, shows the yellow chicks from the moment they are hatched in a massive factory.
The birds are dropped onto a conveyor belt where they are sorted by sex. The males are apparently either thrown alive into electronic mincers or instantly gassed to death.
The females are kept for laying, but only after they have been placed in a machine that clips off the end of their beaks and jabs them against disease.
Even birds that go onto free range or organic farms have to have their beaks clipped, to prevent them pecking other birds.
Viva! visited two hatcheries in Preston. At Tom Barron hatchery they claimed the male chicks were gassed in a giant machine and their bodies packaged to be fed to reptiles. At Fresh Farm Hatchery they claim the birds are thrown directly into a mincer and used for fertiliser.
The birds are sorted for sex according to colour. In the gassing method whole crates of males are put in a chamber and then packaged once they are dead. The mincing or ‘instantaneous mechanical destruction’ is usually a quicker route to death and is widely used in the US.
Both methods are legal and approved by both the Humane Slaughter Association and the RSPCA.
But Justin Kerswell of Viva! said the process is cruel and people should stop eating eggs.
He said hatcheries like the two in Preston supply most of the UK’s egg farming business as hens are replaced every 18 months.
He said even free range or organic eggs that are advertised with idyllic pictures of chicks in the farmyards kill male chicks or use birds from such factories.
"These newborn, uncomprehending male chicks are sorted from females and then either thrown alive into giant electric mincers or gassed in their thousands.
"It is a literal conveyor belt to death journeyed each year in Britain by 30 to 40 million animals, and all to bring the morning egg to our table,” he said.
Martin Shaw, who played Judge John Deed and supports Viva! described the footage as “shocking”.
“Supporting this cruel industry sees the continuation of the slaughter of male baby birds for no reason, other than their sex," he said.
Viva! have reported the hatcheries to the authorities, although neither are doing anything illegal.
The British Egg Information Service said it is necessary to dispose of male chicks because they are no longer of used by the food industry, which uses birds specially bred to grow fast.
A spokesman said that male chicks are usually gassed rather than put alive into the macerating machines and the bodies are a ‘useful source of food’ to captive reptiles and birds of prey.