In 2005, the antibiotic fluoroquinolone was banned by the FDA for use in poultry production. The reason for the ban was an alarming increase in antibiotic-resistant campylobacter bacteria in the meat of chickens and turkeys -- "superbugs," which can lead to a lethal form of meningitis that our current antibiotics are no longer effective against.

Antibiotic-resistant infections kill tens of thousands of people every year, more than die of AIDS, according to the Infectious Diseases Society of America. This problem is on the rise because antibiotics are recklessly overused, especially in the commercial livestock industry, where 80% of all antibiotics manufactured in the U.S. end up.

Fluoroquinolone used to be fed to chickens primarily to stimulate their growth. But why did the banned substance show up recently in eight of 12 samples of "feather meal," the ground-down plumage leftover from commercial poultry production?

This was just one of the mysteries uncovered in a study conducted jointly by the Johns Hopkins Center for a Livable Future and Arizona State University. The research, published last month in the journal Environmental Science & Technology, uncovered a whole slew of other drugs in the feather meal that the scientists had not expected to find there.

Traces of the arsenic compound Roxarsone, for example, were present in almost all of the samples. Farms administer arsenic to chickens to turn their flesh just the right shade of pink that consumers find attractive. Yet, in June 2011, the FDA gave Pfizer 30 days to discontinue selling Roxarsone, a proven carcinogen. So why is it still showing up in our chickens?

Other substances that the scientists found include acetaminophen, the active ingredient in Tylenol, Benadryl, an antihistamine, even Prozac, an antidepressant. Farms feed chickens these mood-altering drugs to reduce their anxiety. Chickens are anxious because they are bred on overcrowded and filthy factory farms. Stressed-out birds develop meat that is tough and unpalatable, so they need to be sedated. Yet, chickens on tranquilizers sleep all the time and do not eat enough. So they are given high doses of caffeine (which was also found in the feather meal) to keep them awake at night to feed and fatten up.

So, here is the deal. We create hellish conditions for our livestock, then we drug them to keep them numb. Then we drug them again to wake them from their pharmaceutical stupor. Then we drug them to grow faster. Then we drug them so their flesh will look healthier. Then we drug them to withstand the disease epidemics that our overcrowding has created.

Then, of course, we drug ourselves every time we take a bite of factory-farmed poultry.

"We were kind of floored," Keeve E Nachman, a co-author of the study told the New York Times. "It's unbelievable what we found." While Nachman says that the levels of arsenic and the witches' brew of other drugs and chemicals in the chicken samples may not be high enough to harm humans, he is not betting his own health on it.

"I've been studying food-animal production for some time," the researcher said, "and the more I study, the more I'm drawn to organic. We buy organic [in my family]."

Organic chickens are bred without artificial growth hormones and antibiotics. They are fed organically grown vegetable foods rather than the ground-up animal products -- bones, feathers, blood, excrement, fishmeal and diseased animal parts -- which their conventionally grown brethren receive. They are also raised free-range with plenty of space, sunlight and opportunities for exercise to keep them healthy. A 2001 study conducted at the University of Perugia found that chickens produced this way actually taste better than conventionally bred birds.

Yet, organic poultry is a lot more expensive to raise. While the market is growing steadily for organic birds, it still comprises less than 1% of the poultry sold in the US today. So, food scientists argue that the standards for conventional chickens and turkeys need to be strengthened.

"We strongly believe that the FDA should monitor what drugs are going into animal feed," Keeve Nachman urged, adding that, based on what the researchers discovered, they had little confidence that the animal food production industry could be left to regulate itself.

Earlier this month, the FDA announced what looked at first glance like sweeping new guidelines on the use of antibiotics in livestock. The new rules, however, are strictly "voluntary," and, while they do recommend restricting the use of antibiotics to stimulate growth, they would still allow them to be prescribed by a veterinarian for animals that are "either sick or at risk of getting a specific illness."

Critics contend that the words "at risk of getting a specific illness" provide factory poultry farms a loophole big enough to drive a truck through. Margaret Mellon, senior scientist at the Union of Concerned Scientists, said in a press statement:

"The outlined process appears to give the companies the opportunity to relabel drugs currently slated for growth promotion for disease prevention instead. Such relabeling could allow them to sell the exact same drugs in the very same amounts."

Public interest groups like the Union of Concerned Scientists say the time has come for the FDA to stop proposing half-measures and demonstrate that it is serious about preventing a looming public health disaster. It needs to ban dangerous antibiotic use in the raising of livestock, and to conduct rigorous on-site inspections to insure that the ban is enforced.

An earlier version of this article appeared in the Guardian UK.