The US Department of Agriculture last week issued a conditional license for an avian flu vaccine for use in chickens, as an outbreak of a newer variant ravages poultry flocks, contributing to the sky high price of eggs.

In the past three years, the U.S. Department of Agriculture (USDA) says about 150 million birds died across the country due to the virus. This month, the USDA granted a conditional license to Zoetis for its Avian Influenza Vaccine.