Factory farming is a huge problem when it comes to influenza and other diseases spreading and mutating. It certainly doesn’t help that farmers are often not given protective equipment like gloves and masks, but even without that, factory farming animals is a huge problem when it comes to the spread of disease.
In this case, it’s farming chickens and turkeys (along with other less common birds) that is the problem with influenza in general since it usually begins in bird populations, but it’s already spread to cattle farms.