India is struggling to contain its worst avian influenza ­epidemic, in spite of culling 3.4m birds and setting up a 5km poultry exclusion zone round the state of West ­Bengal, the epicentre of the outbreak.

The government’s failure to reassure farmers that they will receive fair compensation for birds culled by rapid response teams has left experts scrambling to stop the disease entering the crowded markets of Calcutta and Delhi and led to a crisis of confidence in India’s ­poultry industry.