Thailand, Asia's largest chicken exporter, announced on Wednesday it would cull more chickens in three provinces in an attempt to contain the outbreak.
"We still don't know how many chickens will be destroyed in the end but we need to clean up the whole industry" in affected areas to ensure they stay disease-free, deputy agriculture minister Newin Chidchob said.
"If our officials detect any irregularities (with the chickens) we will immediately destroy them," he said, adding the central provinces of Suphan Buri, Chachoengsao and Nakhon Sawan were under close scrutiny.
The minister said more than a million chickens had been culled since November last year, but precise numbers would be given out next week.
Bird flu link feared
The outbreak of fowl cholera and bronchitis triggered fears of links with bird flu which is gripping several Asian countries and has left at least five people dead in Vietnam.
Thai authorities have said the
country is free of bird flu
Senior officials said no humans had died from the fowl cholera outbreak and insisted that there was no bird flu case in Thailand.
However, the health ministry's disease control department on Wednesday warned the public to eat only well-cooked chicken and eggs to ensure all bacteria, viruses and parasites were safely destroyed.
"The public health ministry wants to reassure the public that eating chicken meat and eggs is still safe, but they should always be well cooked before consumption," department director Charal Trinvuthipong said in a statement.
Thailand has tightened controls - in particular to protect its billion-dollar export industry - by setting up checkpoints to monitor chicken transport, sending officials to slaughterhouses and increasing the number of birds being tested for disease.
Infected falcon found
The bird flu sweeping through parts of Asia has been found in Hong Kong, the government said on Wednesday after tests revealed a wild Peregrine falcon found dead near a chicken farm, had been infected.
The dead bird was discovered in the northerly rural New Territories on Monday.
It was taken for tests by the Agriculture, Fisheries and Conservation Department (AFCD) and found to have the H5N1 bird flu.
The strain is the same as that which has decimated poultry stocks in South Korea, Japan and Taiwan and also led to the deaths of five people in Vietnam.
"The presence of the H5N1 virus in the Peregrine falcon poses no immediate threat to the public," AFCD assistant director Lai Ching-wai cautioned in a statement.