According to The Wall Street Journal, the Justice Department has opened an investigation into egg prices, which have doubled in the past year. The department plans to establish whether egg producers have conspired to inflate prices or hold back supply. The department has already sent letters to several dairy companies instructing them to preserve all documents about their pricing conversations with customers and competitors, as well as any correspondence with Expana, the agency that tracks wholesale egg pricing information. Increasing egg prices—on average, grocery shoppers in America are paying approximately $5 per dozen—have largely been attributed to the worst outbreak of avian flu in the country’s history. The widespread disease has resulted in the deaths of more than 150 million chickens, turkeys and egg-laying hens in the past three years. President Donald Trump previously vowed to get inflation under control after starting his second term. In late February, the Trump administration was struggling to rehire avian flu experts who were fired in the Elon Musk-led federal worker purge, in order to curb skyrocketing egg prices.