NEW DELHI (Reuters) - Authorities in eastern India will start culling chickens and destroying eggs to contain a new outbreak of H5 bird flu, the government said in a statement on Tuesday, as a mutant strain of the virus is spreading elsewhere in Asia. Surveillance was stepped up in West Bengal, a state severely hit by bird flu outbreaks in the past. The federal government is pushing local authorities to ban the movement of poultry and its products, and restricting access to the affected area after samples tested positive for H5, a govt statement said. It has been decided to immediately commence the culling of birds and destruction of eggs and feed material to control further spread of the disease, it said.