(CNBC) The surge in egg prices has stood out in a year when Americans saw their bills balloon across the grocery store.
Average egg prices jumped 49.1% in November compared with those a year earlier — the largest annual percentage increase among all grocery items in that period, according to the consumer price index, a barometer of inflation.
By comparison, the overarching “food at home” category was up 12%.
The increase is even more acute when measured by the cost of a dozen large, Grade A eggs, which more than doubled to $3.59 in November from $1.72 the year-earlier month, according to data from the Federal Reserve Bank of St. Louis.
Bird flu is largely to blame for rising egg prices
Those price dynamics are primarily due to the deadliest outbreak of bird flu in U.S. history, which has killed millions of egg-laying hens this year, according to economists.
“A lot of things are up since 2020,” Bill Lapp, president of Advanced Economic Solutions, a consulting firm specializing in food economics, previously told CNBC. “But the recent spike is extraordinary in the shell-egg as well as egg-product markets.”
About 57.8 million birds have been affected by avian flu in 2022, according to U.S. Department of Agriculture data as of Dec. 28. These figures include birds such as turkeys and ducks.
Bird flu is relatively rare in the U.S. The last bout was in 2015, when 50.5 million birds — the previous record — were affected, according to the Centers for Disease Control and Prevention.
The flu hadn’t emerged in at least a decade or two prior to that, Lapp said.
Here’s why this matters: Avian flu is “highly contagious,” the New Jersey Department of Agriculture said in October. It’s also extremely lethal: It kills 90% to 100% of chickens, often within 48 hours, according to the CDC.
Farmers generally must kill their remaining birds — not by choice but due to federal rules meant to prevent spread, Brian Moscogiuri, a global trade strategist at Eggs Unlimited, an egg supplier based in Irvine, California, previously told CNBC.
About 40 million egg-laying hens — “layers,” in industry shorthand — have died this year due to avian flu, Moscogiuri said. There were 375 million total layers in the U.S. as of Dec. 1, which is down 5% from last year, according to the USDA.
Egg quantity has declined in lockstep. About 8.9 billion eggs were produced in November, down from 9.7 billion in December 2021, according to USDA data issued Dec. 20.
“It’s a supply disruption, ‘act of God’ type stuff,” Moscogiuri said. He called the situation “unprecedented.”
“It’s kind of happenstance that inflation is going on [more broadly] during the same period,” he added.