This is one of Vox's Future Perfect predictions for 2023; they give it a 40% probability.

In 2015, a catastrophic avian influenza outbreak in the US wiped out 50 million chickens and turkeys raised for food. Most of them didn’t die from the disease but instead were culled, or proactively killed (in disturbing ways) to prevent further spread. It seemed like a black swan event, but as of mid-December, over 53 million birds have been culled in this year’s outbreak. Europe set its own bird flu outbreak record this year, too.

Some experts say the highly pathogenic influenza may be here to stay, and there’s good reason to worry they’re right. Usually, avian flu viruses subside during the summer months, but this summer they continued to circulate. European officials say the disease may now be endemic among the continent’s wild bird populations, who spread it to farmed birds as they migrate. And the virus is spreading faster, and to more species — including more mammals — than past outbreaks.

Given the alarm among those who closely track bird flu, increasing calls for vaccination against bird flu (a long-taboo topic among governments and poultry producers), and the fact that this year’s virus hit 47 US states (compared to 21 states during the 2015 outbreak), I think the chance of another disastrous bird flu outbreak is fairly high.

(Vox)

Resolves according to Vox Future Perfect's judgment at the end of the year.

Jan 9, 10:42am: Over 50 million birds will be culled due to US bird flu outbreaks → Over 50 million birds will be culled due to US bird flu outbreaks [in 2023]