When we shop at the grocery store, no longer does the bagger ask, "Paper or plastic?" We get plastic, unless we bring along our own reusable bags. With chicken feed, using your own bags isn't feasible. You get what you get. Last time I went to the feed store for Purina "Start & Grow," I got polypropylene bags. The loaders grumbled about the way the slick bags slide around. By the time I got home they were all over the pickup bed, and we had a heck of a time neatly stacking them in the barn. But that's not the worst of it.

We recycle empty feed sacks by finding good uses for them. Opened out, they make great garden mulch to keep down weeds between rows. They also make handy brooder liners. When the brooder needs cleaning, we roll up the dirtied bedding, bag and all, and toss it in the compost. Poly bags can't be used as brooder liners; they trap moisture that leads to unhealthful mold growth and sick chicks. And they can't be composted.

Unlike paper, plastic is not truly biodegradable. The woven poly strips will eventually separate into small pieces that, past experience with similar products tells me, field mice and wild birds will collect to make nests. That's just another form of petroleum pollution. And any chicken (or other bird) that eats the indigestible plastic strips can die from impaction and starvation.

This guinea keet died after a plastic strip from a poly woven feed sack passed through its digestive system.

I, like a lot of Backyard Poultry readers, prefer natural products. That's one of the reasons we raise chickens. "Start & Grow" is supposed to be all natural, but what's natural about plastic? Polypropylene is a petroleum-based plastic polymer. Like other petrochemicals, it is non-renewable. At a time when we're facing a huge ecological disaster resulting from a botched attempt at oil extraction, and our President is urging the country to wean itself from our addiction to oil, it seems ironic that any company would start using a petroleum based product.

So I called Jackie Jarosz, director of Customer Service at Land O' Lakes Purina Feed. Jackie told me the switch to poly bags was a result of customer requests. As we spoke I came to understand the customers in question are feed dealers, who complained about torn paper bags and spilled feed. Poly bags save the company money by reducing breakage and spillage during transit. Further, because of their lighter weight, they reduce the cost of transportation because more bags of feed can be loaded onto each truck. Poly bags are less expensive to manufacture than paper, and easier to recycle. The upshot of all this is that the folks at Purina feel poly bags, compared to paper, have a lower total carbon footprint. All this is true. Until the bags get to the consumer.

Jackie emphasized that one of the deciding factors in adopting poly bags is recyclability. That's assuming people will actually recycle them. Fact is, the recycling rate of all plastic bags is only about 5%. Still, at Jackie's urging I logged onto earth911.com to find a local recycler that accepts polypropylene. The nearest one listed is 42 miles away, and in a direction I have no other reason to go. Driving 84 miles round trip to recycle plastic bags certainly increases my carbon footprint. And I understand some recycling centers have trouble finding a buyer for poly, so it's sent to a landfill anyway, where it clogs up the works.

Like a lot of people, our family avoids eating food that comes in plastic. We grow chickens so we can have healthful meat and eggs, but now we're faced with feeding our fryers and layers stuff that comes in plastic. Polypropylene is generally considered food safe because it does not leach the same harmful chemicals as other plastics — Bispenol-A (BPA), PVC plasticisers, and phthalates.

But neither is it inert, as researchers learned at the University of Alberta, Canada. In 2008 they discovered that two families of compounds in polypropylene were contaminating their experiments: quaternary ammonium biocides-anti-bacterial agents (added during the manufacture of plastic), and oleamide and related chemicals (used to improve the properties of plastic). As lead researcher Andy Holt and his colleagues pointed out in the journal Science, oleamide and related additives leach into foods stored in polypropylene containers.

Dr. Holt's laboratory researches how human enzymes work at the molecular level. Oleamide is a molecule that is naturally found in the human body and contributes to normal functioning, but the health effects of ingesting molecules that are structurally similar to oleamide have yet to be determined. However, Dr. Holt and his colleagues have shown that compounds in polypropylene interact with, and change the behavior of, human enzymes and brain receptors. So much for the food safety of polypropylene.

To be fair, Purina is not the only company moving toward plastic, but it's my brand of choice. Or has been until now. Since I'd rather fight than switch, I'm hoping Purina will do the right thing — drop the plastic bags and stick with paper. Jackie told me the folks at Purina appreciate hearing from customers and they seriously consider all feedback. So if you don't care to buy chicken feed in polypropylene bags, call (800) 227-8941 or click on "contact us" at http://poultry.purinamills.com and let them know.