Dear Mark: Industrial Duck, Topical Seed Oils, and Costco Rotisserie Chicken Bones

We can’t always make the perfect Primal choices. We simply don’t live in a world that affords us the opportunity, and short of being whisked away in the night by an elvish boy with green tights, a fairy companion, and the ability to fly, we’re stuck here for the duration. Let’s make the best of it, huh? I think I do a pretty good job at that, here on this blog, but sometimes there are questions that I have yet to address. Like what to make of industrially-raised duck, or whether or not you should still apply those seed oils – which you’d never eat if you could help it – to your face and body as moisturizers, or if carcasses from industrially-raised chickens are still worth using to make stock. These are questions that most people never even think about, but you have (or at least some of you), and I aim to provide a helpful answer.

Let’s go.

I know industrially raised chickens and cows are nutritionally not the best, but what about duck? Are ducks raised any better than chickens since they are eaten less frequently?


Unfortunately, ducks are also industrially raised:

Standard duck feed consists of mostly corn and soybean, with a mix of wheat “middlings” (an assortment of wheat bran, germ, and flour), vitamins, minerals, and sometimes meat and bone meal. Corn is by far the biggest contributor to calories. No bugs, greens, worms, or small fish for these ducks.

Standard operating procedure sticks ducks indoors to keep predators away (and reduce the need for open space). Ducklings (whose beaks are usually removed) get a half square foot of space, an allowance that eventually increases to two square feet as the duck grows.

In industrial duck farms, ducks generally have zero access to water (probably for the best; if they did have access to a body of water in their enclosures, it would become pretty foul very fast) save for the water they drink from nipple feeders. Ducks are water fowl; the fat which we prize so much exists to provide natural flotation. You could argue about whether or not ducks mind being in close quarters with other ducks, but I don’t think you can argue against a duck’s natural predilection for flapping around happily in a body of water.

Nutritionally, I’d wager that industrial duck might be “better” than industrial chicken. Ducks have far less PUFA and more saturated fat. I’ve also never heard of Peking chicken, so duck wins that one, too.

Dear Mark,

I’m hoping you can shed some light on the subject of seed and plant oils used for skin care. I long ago ditched chemicals and other nasties from my personal care products, but in light of what I have now learned about how unhealthy some oils are for our health, I’m wondering if the same goes for putting them ON our bodies as in them. A favorite body oil of mine contains grape seed oil, sunflower oil, apricot kernel oil, soybean oil, and rice bran oil. They’re supposedly all cold-pressed, organic, non-GMO sourced, which I know is a step in the right direction, but is it enough to make putting soybean oil on your skin a good thing? I’ll freely admit that I’ve had great results from this product, which is why I’m asking – I’d rather not give it up if I don’t have to!

Thanks, so much, for all you do!

M 🙂

PS: I can already hear the chorus from the comments… “Coconut oil!!” I’ve tried it, and it worked pretty good as far as moisturizing goes, but sadly I think I’m actually mildly allergic to it. Olive oil is a no-go for my skin, too.

I wouldn’t worry too much about your body oil. The reason why we (or at least I) recommend against eating those oils is the amount of omega-6 linoleic acid they contain. That is, introducing those oils to our digestive system leads to their digestion, incorporation, and the resultant pro-inflammatory cascade. Applying some soybean oil to your skin isn’t the same as ingesting that same soybean oil. Or is it?

Strangely enough, there is preliminary research suggesting that certain segments of the population – namely, preterm infants – might be able to absorb topically applied fats and draw upon them as a source of calories (PDF). And some older studies show that topical application of essential fatty acids (EFAs) can correct EFA deficiencies, such as with a nineteen year old patient subsisting on a fat-free nutrient infusion, or in newborns with low plasma levels of linoleic and arachidonic acids. It’s not foolproof, though, as other studies suggest that topical application is inadequate to prevent fatty acid deficiencies. It’s probably a case of the dose determining the response, as 100 milligrams/kg body weight of linoleic acid (a paltry amount) was insufficient to affect serum EFA levels in one study using infants.

If you’re bathing in the stuff, you might be absorbing an untoward amount, but I doubt you’re doing that. Plus, if it’s improving the health of your skin, I highly doubt it’s also promoting inflammation. If you’re really worried, just use some coconut oil and olive oil. (Just kidding.)

Hi Mark,

I guess this question is really about food quality:

Yesterday, I was short on time and, for convenience, I picked up a rotisserie chicken from COSTCO. I know it was still a primal choice from a meat perspective, but since it was not organic (and not even close to free-range) I threw out the carcass. A part of me wanted to use it for bone broth, but I wasn’t sure if that was a good idea since it had likely been treated with antibiotics and hormones. What do you think?

Thanks for all you do!


Ah, yes, the famed Costco rotisserie chicken. It’s $4.99, juicy, massively-breasted, pumped full of brine, and delicious in spite of your mind’s protestations to the contrary. It’s said that even Julia Child was a big fan.

It’s actually illegal to treat chickens with hormones in the US, so your chicken carcass from Costco won’t have any hormone residues.

Antibiotics are widely used in poultry farming, even the banned ones on occasion. And studies indicate that antibiotic residues do show up in animal bones. However, heating has the potential to destroy antibiotic residues in bone, although not as easily as it does in muscle meat. One study found that the only way to completely eradicate the presence of tetracycline in chicken bones was to subject it to 121 degree C autoclaving (a high pressure steaming) for 60 minutes; it did not test boiling. This study (PDF) found that boiling was effective at removing antibiotic residue from chicken meat, but I’m not sure that’s helpful for making broth, since some of the residues migrated to the boiling liquid (which you’ll be drinking, rather than discarding).

Broth is an important addition to the Primal way of eating, and I honestly wouldn’t stress about adding a Costco carcass to the pot every once in awhile. After all, the levels of antibiotic residues that show up in meat and bones from treated animals pale in comparison to the levels you’ll get from an antibiotics cycle prescribed by your doctor. And even though those chickens were reared on pesticide-laden corn and soy and antibiotic-treated water, their bones are still made of the same basic stuff as the bones of a pastured chicken. You’ll still get gelatin, calcium, and a host of other nutrients when you make broth. You just might be getting a dose of other, undesirable stuff, too. I think the value of the former outweighs the potential harm of the latter, especially if that’s the only bone-based dietary input you’re getting.

If that Costco chicken was just a blip, an aberration, and you normally make broth from better bones, I would have done the same thing you did.

Okay, that’s it for today’s questions. Let me know your thoughts on CAFO duck, soy oil moisturizers, and Costco chickens. Thanks for reading!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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