In the last five days above five hundred chickens have been died in the two poultry farms of Chitrapar and Devpar villages of the district. “The matter was not reported by the poultry farm owners, his department has reported it to the district Magistrate R P Singh the DM has directed the officials of the department to make an on the spot assessment of the situation” Chief veterinary officer of the district S.K. Bhagat said. S.K. Bhagat said it may be adding prima facie cold and diarrhoea appear to be the cause of the death. Meanwhile, round-the-clock vigil was being maintained in the Bakhira bird sanctuary area which is in about 10 kms radius of the vicinity of the villages where the deaths have been reported, Bhagat added. Bird flu has ravaged 13 districts of West Bengal.