Little Lil, a Columbian blacktailed cross hen, is the smallest of her flock but regularly lays eggs measuring 10cm across - more than twice the size of a normal egg.

Youngsters at Raikes Centre pupil referral unit in Gloucester have been unable to measure the weight of the eggs because they exceed 8oz, the maximum their scales will reach.

When pupils cracked open the latest oversized egg they found a yolk, an egg white and another small but complete egg on the inside, like a Russian doll.

The six-month old hen has only been laying since October but once a month she forces out an egg measuring an eye-watering 10cm by 8cm.

Teacher Kate Farminer, 54, said: "We've got four pet chickens here and Little Lil is by far the smallest and also the quietest.

"So we were amazed when she started producing these enormous eggs - you wonder how she gets them out.

"The first time it happened the egg broke but the latest one was intact.

"We've got another two spare so this time our curiosity got the better of us and we took a look inside.

"We couldn't believe it when we found another egg inside - maybe she's a Russian chicken."

Little Lil lives with three other pet chickens Auntie Madge, Auntie Edie, and Auntie Doreen. Her eggs normally measure 4cm by 7cm.

The centre's three classes of children aged between four and eleven also keep pet rabbits and chickens.

According to Guinness World Records, the largest ever egg was laid by a Black Minorca hen in England in 1896 and weighed nearly 12oz.

by:telegraph