Children at a Gloucester primary school are very confused by the eggs their smallest pet chicken is laying.

And their teachers are just as puzzled.

Just how is Little Lil managing to lay eggs the size of a large orange?

The chicken stunned the Raikes Centre pupil referral unit after laying enormous eggs the size of a large orange.

Little Lil has laid four 4in (10cm) whoppers which are more than twice the size of a normal egg – some of the children will tell you they are actually dinosaur eggs.

Teachers have been unable to measure the weight of the eggs because they exceed 8oz – the maximum their scales will reach.

When children cracked open the latest egg they found a yolk, an egg white and another egg on the inside – like a Russian doll.

Teacher Kate Farminer, 54, has no explanation for what has caused Little Lil – the smallest of four hens kept at the school – to lay the whoppers.

"Little Lil is by far the smallest and also the quietest," she said.

"We have four chickens Auntie Madge, Auntie Edie, Auntie Doreen and Little Lil. We discovered the big egg last weekend and separated the chickens to see which one had laid it and were flabbergasted when it turned out to be Little Lil, the smallest of the lot.

"We were amazed when she started producing these enormous eggs – you wonder how she gets them out.

"The children think they are dinosaur eggs. It's very exciting for the children to have something special like this."

Little Lil, a Columbian blacktailed cross, is six months old and began laying legs in October. She lays a normal-sized egg every day, but one enormous one each month.

They are 4in (10cm) long and 3.1in (8cm) across, compared to 1.5in (4cm) by 1.2in (3cm) for a normal egg.

"The first time it happened the egg broke but the latest one was intact," said Mrs Farminer.

"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."

The centre's three classes of children aged between four and eleven also keep pet rabbits and chickens. They have class pets each year as part of their personal development programme.

They are the joint responsibility of the children and teachers and spend each night at Mrs Farminer's house in Gloucester.