Her owner, Mark Cornish, said the egg is about 9cm (3.5in) high and has a circumference of 21cm (8.3in).
Mr Cornish, 36, of Ipswich, said he was extremely shocked when he pulled the enormous egg out of the hutch at the bottom of his garden.
‘I was so surprised, I thought a goose must have got in there by mistake,’ he said. ‘It does not look as though a chicken would have laid it. I think it is four times bigger than a normal egg.’
‘The problem is the shell is paper thin. It’s already had a crack in it so I think I might have to eat it tonight.
A spokesman for Guinness World Records said: ‘The largest hen egg was a five-yolked egg measuring 31cm (12.2in) around the long axis, 22.8cm (9in) around the short and weighing nearly 340g (12oz). It was laid by a Black Minorca at Mr Stafford’s Damsteads Farm, Mellor, Lancs, in 1896.’