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, say news reports.
The chick is fully formed and healthy but the mother has died.
The government veterinary officer in the area asserted that he had never seen anything like it before.
PR Yapa, the chief veterinary officer of Welimada, where it took place, looked into 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 till the time it hatched.
A post-mortem conducted on the hen’s body revealed that it died of internal wounds.