I agree to a point but it is also about biosecurity. I know that if I were raising a large number of birds for resale (eggs, chicks, meat, whatever) I wouldn't want anyone just walking around. You never know what they may have on their shoes etc that is not a problem in your flock.
I know about the biosecurity aspect and I agree -- a lot of this came up after some of the Homeland Security Act was initiated
I just wonder about security though when a large percentage of the employees are undocumented illegal workers, who are responsible for the increase in diseases (tuberculosis, pertussis, and polio and others) that had been virtually wiped out in the United States until the past few years