(CNN) - The United States is experiencing an egg shortage due to avian flu, causing more empty shelves and fewer choices at the grocery store.

And the situation may not improve anytime soon.

In November and December alone more than 17 million egg-laying hens died as a result of the virus, according to the U.S. Department of Agriculture.

It will take months to replace those flocks.

Fewer egg-laying hens means fewer eggs and higher prices.

According to Neilsen IQ data provided by the American Egg Board, the average price of a dozen eggs of any kind at the end of December was $4.33 -- up nearly 25% from the beginning of November.