The current global outbreak of highly pathogenic avian influenza (HPAI), a form of bird flu (H5N1), began in early 2022 and has resulted in the deaths of over 58 million chickens and turkeys. This group, of course, includes egg-laying hens, and experts fear that the virus will continue to spread. The current outbreak led to a severely strained egg supply and caused skyrocketing prices and record profits for producers early in 2023.

Two egg cartoons on a grocery shelf.
The price of eggs has increased over the last year because of an avian flu outbreak that has impacted chicken farms across the country. Eggs are for sale on an almost empty shelf at a grocery store in Kansas City, Mo, on Jan. 23, 2023.
Aaron M. Sprecher/AP

Experts worry the current migration season could cause the avian virus to spread further or mutate among poultry. While it is not currently endemic to U.S. poultry flocks, the virus reaching that point could have a significant impact on food safety, Maurice Pitesky, a poultry health professor at the University of California, Davis told Food Dive.

A car is sprayed down by two people on a road in the countryside.
Workers spray a vehicle before it leaves a large-scale commercial poultry farm operated by Daybreak Foods, which has been designated a "biosecurity area" after an avian influenza outbreak in Eagle Grove, Iowa, on May 17, 2015. 
Scott Olson via Getty Images
Millions of dead chickens and turkeys decomposing in fly-swarmed piles near dozens of Iowa farms, culled because of a bird flu virus that swept through the state's large poultry operations on May 7, 2015.
Iowa Department of Natural Resources/AP
Turkeys stand in a barn on the Moline family turkey farm in Manson, Iowa, on Aug. 10, 2015. The Moline farm was the first Iowa farm to restock after the bird flu outbreak that killed 48 million birds in 15 states.
Charlie Neibergall/AP

The impact of bird flu

In 2015, avian influenza subtype H5N2 was identified in a series of chicken and turkey farming operations in the Midwest, according to USDA. That outbreak affected nearly 50 million birds and was the costliest animal health emergency in the history of USDA, the government agency reported.

By summer 2015, more than 43 million birds were culled, including nearly 30 million in Iowa alone, the state with the largest egg operations, the Los Angeles Times reported. The average price of eggs increased 120% between April 22 and May 30, 2015. The effects, however, were seen nationwide, with prices in California up 71% in the same timeframe. Cases subsided in 2016, according to the CDC.

The current bird flu outbreak, which started in January 2022, has since spread to 47 states, the CDC said. By November 2022, 50 million birds were infected. The government has not reported any new cases of bird flu among commercial or backyard flocks since late December, meaning the spread of the virus may have temporarily subsided.

A person uses a instrument to collect samples.
Microbiologist Anne Vandenburg-Carroll tests poultry samples collected from a farm located in a control area for the presence of avian influenza at the Wisconsin Veterinary Diagnostic Laboratory in Madison, Wisconsin, on March 24, 2022.
Scott Olson via Getty Images

Following months of increases, prices of eggs at grocery stores decreased 6.7% in February, according to the Consumer Price Index from the Bureau of Labor Statistics.

The current strain of the bird flu virus, H5N1, was first identified in 1996 in geese in China, and in people in Hong Kong in 1997.

Two people gather chicks into a corner.
Government workers collect chickens at a Hong Kong farm after the government ordered the slaughter of all 1.2 million chickens in a move to stamp out a mysterious bird virus that killed four people on Dec. 29, 1997. 
Larry Chan/Pool/AP

“At the end of the day, this is a continuum of the same outbreak that started back in 1996,” Dr. Malik Peiris, chief of virology at the University of Hong Kong, who has helped oversee responses to several bird flu outbreaks in Southeast Asia told the New York Times. “Really, it never went away.”

HPAI is carried by aquatic birds, such as ducks, that can transmit the virus rapidly to domestic poultry through contact with bodily secretions, according to the CDC.

Several people walk in all protective gear.
South Korean soldiers and national veterinary and quarantine service personnel pass a roadblock on their way bury hundreds of carcasses at a duck farm affected by a highly pathogenic avian influenza in Cheonan, Seoul, on Dec. 22, 2003.
Chung Sung-Jun via Getty Images

The spring migration, which is happening currently and is projected to conclude in May, has experts and industry figures worried that it will continue to spread to commercial flocks.

Several vaccines against HPAI have been developed. In March 2023, the Biden administration announced plans to test a vaccine for poultry, potentially to use on a large scale in the United States. 

A hand holds a large and small egg.
A barnyard hen's egg (top) and a quail's egg sit in the palm of a hand in 1950.
Douglas Grundy/Three Lions via Getty Images
A farm worker packs eggs in the 1930s.
General Photographic Agency via Getty Images
Innovative engineer Mr. Reginald Carter proudly poses with his new invention, the Egg-O-Matic, which simplifies the messy business of egg buying on May 4, 1960.
Chris Ware/Keystone Features via Getty Images

A bit of egg history

Humans have eaten eggs for about 6 million years. The first people to eat eggs most likely took them from nests in the wild and ate the eggs raw, according to the American Egg Board.

Wild jungle birds were domesticated for egg production in India by 3200 BC, the American Egg Board reported, and it is thought that ancient Egypt and China were the first to domesticate hens.

A piece of paper with illustrations.
Joseph Coyle’s design patent for the egg carton.
US Patent 

The egg carton was invented by Joseph Coyle in 1911 in Smithers, British Columbia. Lore has it that the carton was created to resolve a dispute about broken eggs between a farmer and the owner of a hotel. Early egg cartons were made of paper.

The U.S. egg industry began as a backyard business. In the early 1900s, farmers raised hens to provide eggs for their families, according to The American Egg Board. Extra eggs were sold at local markets. As the demand for eggs grew, farmers increased the size of their flocks. The farmers had more eggs to sell, but they had more problems, too. Conveyor belts and egg washers were introduced.

Two people wash eggs.
Farm girls washing eggs, before they go into an incubator for post war poultry re-stocking on May 1, 1945.
Fox Photos via Getty Images

By the early 1960s, the egg industry was shifting from small farm flocks to larger commercial operations. Today, robots are common in commercial operations.

Eggs are suction to a machine for packing.
An employee works at the egg sorting and packing line of the Labinsky breeding poultry plant, in Krasnodar region, Russia. The enterprise produces incubation and commercial chicken eggs. 
Vitaly Timkiv/Sputnik/AP

Iowa leads the nation with more than 14.8 billion eggs produced annually. Ohio is next in line, producing 7.9 billion eggs each year. In 2022, around 9.1 billion dozens of eggs were produced, according to Statista data.

A person stands in the middle of two windows of a turkey coop.
Bill Powers checks on his flock of white turkeys, which have been kept under shelter all year to prevent exposure to avian influenza, at his family's farm in Townsend, Delaware, on Nov. 14, 2022.
Nathan Howard via Getty Images

In the U.S., eggs are washed. In the UK and the rest of Europe, eggs usually are not washed and do not require refrigeration since their cuticle is undamaged. Washing the cuticle cleans the shell, but erodes its cuticle.

Colorful eggs are sprayed with paint.
Chicken eggs are colored for Easter at Baumeister Frischei egg and chicken farm in Breckerfeld, Germany on April 10, 2014.
Sascha Schuermann via Getty Images

The Easter Egg may symbolize religious traditions, but it’s believed that the origin of eggs being part of the beginning of spring is actually a pagan one. According to the Los Angeles Times: The pre-Christian Ukrainians thought the egg personified the coming of spring ⸺ a celebration of the rebirth after the long death of nature in winter. They began to follow the pagan ritual of coloring eggs as a form of thanking the sun for warming the Earth  an event that became an essential component of Easter celebrations as they are known today.