It’s the Buy-One-Get-One-Free special stores don’t advertise: Buy some chicken, get some meds for free.

And just to make it more convenient for everyone, the drugs aren’t in their own package — they’re already inside the chicken.

Chickens raised on factory farms are being fed everything from banned antibiotics to painkillers — and some are even poisoned with arsenic — all in the name of raising the fattest and pinkest possible birds in the shortest possible time.

Now, two new studies on chicken feathers (which hold traces of drugs and other toxins fed to the birds) show just how many meds are pumped into them — and remember, whatever that chicken eats is what ends up on your plate on Chicken Night:

Caffeine: You know people who seem to eat every waking minute, right? Chickens are like them. Keep them awake longer, and they’ll eat more and get fatter. But caffeine also makes chickens jittery (just like it does to some people), and since jittery chickens have tougher meat, they need something to help them to relax before they turn into tough old birds.

Prozac: One feather-meal sample from China found this antidepressant, and it’s almost certainly there to help counter the caffeine and keep the chickens relaxed so their meat doesn’t get leather-tough. And it’s not the only drug that can have that effect.

Benadryl & Acetaminophen: These drugs turned up in the U.S. samples, and not because the chickens have allergies or need pain relief. It’s because, like Prozac, these drugs can also relax the chickens and help keep the meat tender.

Antibiotics: Factory farm chickens are kept in such cramped and filthy conditions that illness is a much bigger threat than the wolf ever was. So the birds are drugged to preemptively protect them from a rapidly spreading infection — and, conveniently, the drugs also help them to gain weight. The researchers found a class of antibiotics banned from poultry… but it looks like that ban is about as strong as a rubber chicken.

Arsenic: It’s crazy, but this is actually allowed. Arsenic kills two birds with one stone (so to speak) because it kills bacteria and keeps the meat nice and pink. The problem, of course, is that it’s arsenic — and when you eat a bird fed this poison, you’re getting a little dose of poison yourself.

It’s enough to keep chicken off the menu for good, but you don’t have to go that far. Just go organic instead.

And for more on food ingredients and additives — including a few you just won’t believe — keep an eye on your inbox on Sunday for my Weekend Roundup.

I always get a kick out of the fridge in my local 7-11. It’s loaded with drinks that make all kinds of promises.

Energy is the most common one, of course, but others promise everything from “focus” to “calm” to “concentration.”

It’s a laugh, because no matter what promise they make, most of these drinks have the same basic ingredients: sugar, water, and artificial flavors combined with small amounts of vitamins or large amounts of caffeine.

In some cases, those vitamins can deliver on the promise made by the label — just not in the tiny amounts you’ll find in the drink. You’re always better off just taking it as a supplement.

And in at least one case, you don’t need to swallow a thing — drink or supplement — to get the benefits.

Rosemary, the fragrant herb often used in soups and meat dishes, is so good at helping you to focus that just the scent alone will do the trick.

Twenty people were given a whiff of rosemary followed by a series of cognitive tests and mood assessments. The stronger the smell, the better they did on both — although the impact on mood was nothing compared to what it did for cognition.

Believe it or not, that’s not even the surprise here. Other studies have also shown that the very smell of rosemary can give your mind an extra gear.

No, the real surprise is that blood tests revealed the presence of 1,8-cineole in the blood. That’s the essential oil found in rosemary, somehow turning up in blood after inhaling the mere odor of this stuff.

The researchers say that means the aroma alone acts as a “therapeutic drug” and are already talking of how they might one day make meds out of fragrant herbs such as rosemary, peppermint, and lavender.

But why wait for meds and their inevitable side effects when you can go straight to the source?

Rosemary is available right now, for cheap, and if I was in college I’d be practically stuffing it up my nose at test time.

Might sound crazy, but a better grade is a better grade.

Since my test-taking years ended long ago, I plan to use rosemary differently — like next time I need help finishing a Sudoku puzzle or locating missing socks.

Some great news for women who already love their cuppa joe – your daily caffeine boost can also slash your risk for one of the most common cancers.

A new study finds that women who drink at least two cups of caffeinated coffee per day may have a dramatically lower risk for endometrial cancer.

Researchers surveyed more than 60,000 Swedish women over 17 years and found that 1 percent of them ultimately developed endometrial cancer – which affects the cells lining the uterus.

Since this cancer tends to disproportionately affect older women, the average age of the diagnosis was 67.

But the researchers found that women who drank at least two cups of caffeinated coffee each day had a lower risk of getting that cancer – sometimes significantly so, depending on how much they drank and how much they weighed.

On average, each additional daily cup of coffee lowered the risk for this cancer by 10 percent, according to the study published in the International Journal of Cancer.

The researchers found that heavier women got the biggest benefits. Overweight women got a 12 percent reduction in risk for each additional cup of coffee, while obese women were able to slash their risk by 20 percent for each cup.

But since previous studies have found a strong link between obesity and this cancer, I don’t think it’s a good idea to remain overweight and simply drink coffee to reduce your risk.

To get the best of all worlds, lose the weight and keep sipping that joe. You’ll lower the risk for endometrial cancer, but you’ll also get so many other benefits.

Coffee alone has been linked to a decreased risk of Parkinson’s disease, colon cancer, cirrhosis of the liver and even gallstones. Caffeine has also been shown to help prevent headaches – in fact, it’s the secret ingredient in a couple of common over-the-counter headache pills.

In some people, however, caffeine can make certain headaches worse – so know your body on this one.

Losing weight will also give you a health boost far beyond a lower risk for endometrial cancer. You’ll look better, feel better, lower your risk for heart disease and have a much lower chance of joining the growing ranks of America’s diabetics.

And if that’s not good enough for you – then it’s time to wake up and smell the coffee.

Most children already have boundless energy.

But today’s kids are different from those of previous generations, for several reasons.

First, many of them have already been placed on what I call the high-carb Torture Chamber Diet, robbing them of some of that natural energy.

Secondly, many of them are already hooked on caffeine. And recent studies show us that this is one substance they shouldn’t be near at that age.

One study found that kids who have too much caffeine are staying up well into the night, when their growing bodies should be at rest.

Most kids need at least nine hours of sleep per night, but too many of them aren’t getting that. Instead, the study found that they’re sending text messages, playing video games and surfing the Internet.

The study, published in the June 2009 issue of Pediatrics, found these kids – even those who consume caffeinated beverages – are also more likely to nod off during the day.

The researchers looked at 100 children 12-18 years old, and found that a third of them dozed off in school an average of twice a day, while some conked out up to eight times a day. Half of the kids with driver’s licenses said they felt drowsy behind the wheel.

Meanwhile, another study shows what can happen to kids who get too much caffeine.

Researchers in Italy looked at the case of a 13-year-old boy who was admitted to a hospital after chewing two packs of a caffeinated gum. The total caffeine in the gum wasn’t too much by adult standards: roughly equal to three cups of coffee.

But the boy – who had no illicit drugs in his system, by the way – grew agitated and aggressive, which was not normal for him. His heartbeat and breathing rapidly increased, and his blood pressure rose.

The case study, published in the May 30 issue of The Lancet, shows what can happen when someone with no caffeine tolerance – like a child – consumes the stuff.

I’ve got nothing against a couple cups of coffee or tea for most adults.

But kids shouldn’t be near this stuff, especially since they tend to get their caffeine from sugar-laden sodas and energy drinks.

This is the beginning of a lifetime of unhealthy habits and poor sleeping patterns.

I know it’s not easy to control what your teen eats and drinks, but it’s important to know how these things might be impacting their body.

Banning soda and energy drinks might not be the most popular move in your home – but it’s the right one.