A Sri Lanka hen has given birth to a chick without an egg, in a new twist on the age-old question of whether the chicken or the egg came first.

Instead of passing out of the hen's body and being incubated outside, the egg was incubated in the hen for 21 days and then hatched inside the hen.

The chick is fully formed and healthy, although the mother has died.

The government veterinary officer in the area said he had never seen anything like it before.

PR Yapa, the chief veterinary officer of Welimada, where it took place, examined the hen's carcass.

He found that the fertilised egg had developed within the hen's reproductive system, but stayed inside the hen's body until it hatched.

A post-mortem conducted on the hen's body concluded that it died of internal wounds.

The BBC's Charles Haviland in Colombo says that the story has made headlines in Sri Lanka, with the Sri Lankan Daily Mirror's concluding: "The chicken came first; not the egg."