Millions of chickens were killed earlier this year

Tests are being carried out after hundreds of chickens died at a farm in the central province of Ayutthaya.

A deadly strain of bird flu swept through Asia earlier this year, killing or forcing the authorities to cull tens of millions of birds.

The disease also spread to humans, causing the deaths of 16 people, including eight in Thailand.

Chickens at the farm in Ayutthaya began to die about two weeks ago, according to farm owner Veera Sripramong.

"We are investigating this case because the death of the chickens on the farm is unusual. There is a possibility that it could have been caused by the bird flu virus," said the head of the Livestock Department, Limlaemthong.

"We have sent samples for lab testing. The result is due within days," he told Reuters news agency.

Small outbreaks of bird flu also have been reported in neighbouring Vietnam in recent months.