(NEXSTAR) – Eggs are nearly 40% more expensive now than they were a year ago, the Labor Department said this week. It’s about to get even worse, one expert says.

Patrick Penfield, a professor and supply chain expert at Syracuse University’s School of Management, expects egg prices could climb as much as 20% more in 2025 as the avian flu epidemic shows no signs of slowing down.

The massive bird flu outbreak has already led to the death of more than 100 million egg-laying hens. Anytime the virus is detected, every bird on the farm has to be killed to limit the spread of the disease.

Once that happens, it can take about five months for a chicken farmer to recover, Penfield explained. “Once a hen is five months old it can lay about one egg per day,” he said.

The quick and severe constrain on supply has led to skyrocketing prices. A dozen eggs costs about $4.15 on average, according to the Bureau of Labor Statistics. It’s much higher – nearly $9 – in places like California, Penfield said.

California, Nevada, Washington and Oregon require all eggs sold in their states to be cage-free, and that’s driving up prices even further in those states. Because the flu is spread through the droppings of wild birds as they migrate past farms, allowing chickens to roam freely actually puts them at greater risk of catching the virus, said Chad Hart, a professor and agricultural economist at Iowa State University.

At this time, there’s no effective vaccine or medication to protect against the virus, leaving farmers in a tough spot.

“Hopefully, hens will have start to develop some type of natural immunity to the bird flu, but we have not seen that yet and it will take many years for that to happen,” Penfield told Nexstar. “Also, if they do, we do not know if this immunity would protect hens if the bird flu virus mutated. The only recourse you have as an egg farmer is to employ biosecurity practices such as eliminating exposure to wild birds, limiting human interactions, covering enclosures, reducing large puddles and standing water.”

Egg prices peaked two years ago, in January 2023, when a major bird flu spike drove the average cost to $4.82 a dozen nationwide. Penfield predicted we’ll surpass that price by mid-February or sooner.

The Associated Press contributed to this report.