Since the Wuhan coronavirus is all over the news, this would be a good time to point out one of the long-standing problems with animal agriculture: it is a major vector for disease. Covid-19 probably entered the human species through meat consumption—likely through a market in China selling pangolin meat (https://www.nature.com/articles/d41586-020-00548-w).
Many diseases originate in this way—that is, they start as diseases of some nonhuman animal species, they enter human populations when a human eats meat from an infected animal, and the disease then mutates and spreads through human populations. This is also thought to be the origin of AIDS—specifically, humans in Africa eating meat from chimpanzees infected with simian immunodeficiency virus (https://www.theaidsinstitute.org/education/aids-101/where-did-hiv-come-0). In recent decades, we have seen avian flu (H5N1), mad cow disease, swine flu, and SARS—all transmitted from animals to humans through animal agriculture.
Now, if one knew that one was transmitting a deadly disease to human populations, this would certainly be a rights violation—indeed, it would be a form of mass murder. If one does not know, then one is merely unknowingly killing people. So that meat market in China—and the customers who patronized it—have now (unintentionally) killed thousands of people. In the case of AIDS, tens of millions have been killed.
By now, we know very well that we are always incurring risks of introducing deadly diseases into the human species, as long as we continue animal agriculture. Of course, the probability of transmitting a deadly disease to the human population is very small for any given case of meat-selling or consumption, but, in the age of globalization, it is a risk that one imposes on people all over the world. We never know when the next outbreak will occur, but we know that there will be further disease outbreaks.
But surely, you might argue, it is permissible to incur some risk of killing other people, for some purposes; otherwise, nearly every activity would be immoral. True—but equally obviously, some risks are unacceptable. Thus, for example, it is permissible to drive to work normally, but it is not permissible to drive while drunk.
How much risk is acceptable depends on what one’s reasons are for incurring the risk. May one play Russian roulette for fun (with unwilling other people)? No. What if your gun has a thousand barrels (so the probability of killing someone is only 1/1000)? Or a million? Or a billion? Intuitively, all these are still impermissible—even when the risk of killing someone is much less than the risk of killing someone in a traffic accident. That is because there is no good reason for playing Russian roulette with anyone; thus, even a small risk imposed on unwilling victims is an impermissible rights-violation.
So, whether the meat industry, and meat consumers, are impermissibly violating the rights of the other people around them depends on the reasons they have for creating these risks. If, as I contend, they have no good reasons (indeed, they have on balance strong independent reason not to create this risk), then selling and consuming meat is an impermissible rights violation.