Yeah it is 100% because of massive chicken and beef farms. I saw some scientists who study these diseases say basically, this is an important enough issue (and is going to keep happening for as long as we're doing factory chicken farming) that we should be transitioning away from factory chickens and back to small independent farms that don't create such perfect petri dishes for human-harmful diseases. Sadly their advice has a 0% change of being implemented before something really, really bad happens because of it.