Few issues are more contentious these days than debates about the impact of so-called “factory farming.

Well, maybe “sequestration” raises a few more hackles at the moment, but certainly, the emerging criticism of animal agriculture as it’s practiced in the 21st century more and more tends to revolve around its environmental impact.

Central to the argument that activists roll out when they attempt to broad-brush the problems for which meat and poultry production is allegedly responsible is its eco-footprint. According to this argument, raising livestock, providing them feed, housing and ultimately transportation to a processing plant is a huge waste of energy, land, water and just about every other input that can be quantified.

The attack connects seamlessly with the notion of sustainability as it relates to food production, and alternative agriculture enjoys lots of traction simply by positioning themselves as “we’re not factory farming.”

Interview: The incredible egg storyEnter Prof. Hongwei Xin, director of the Egg Industry Center at Iowa State University. Among other projects, Xin has conducted a detailed comparison of the efficiency—and thus sustainability—of egg production today versus 50 years ago.

Think about that for a moment. Isn’t the basic message of most natural, organic “sustainable” food production alternatives based on an unspoken (and highly romanticized) version of farming way back when? Consumers are told unequivocally that going “back to Nature”—ie, back in time—is intrinsically more sustainable.

That’s why Prof. Xin’s research is so important, in that it provides strong support for the idea that modern production helps—not hurts—efforts to mitigate resource depletion, improve land-use efficiency and maintain the sustainability of food production overall, and animal agriculture specifically.

To explore the data that Prof. Xin has compiled, and to better understand the implications of his research, he spoke with Dan Murphy, Contributing Editor for Vance Online Networks (Drovers/CattleNetwork).

Q. First, professor, can you explain in more detail about the specific sources you relied upon in compiling comparative 1960 egg production figures? Do you feel those data were reliable?

Prof. Xin: That is a good question. When we researched [production] back in the 1950s and 1960s, there were quite a few books, studies in journals and various industry publications that we feel gave us an accurate idea of production levels back then.

Q. So you’re confident that in comparing data then versus now, it’s an apples-to-apples comparison?

Prof. Xin: Yes, we believe our data show an accurate comparison.

Q. All right. You stated in a presentation to the International Production & Processing Expo earlier this year that “Pullets now consume 48% less feed than in 1960” and that “feed efficiency was 42% greater in 2012 versus 1960.” Could you explain those two figures, and why such a significant difference?

Prof. Xin: In the 1960s, we calculated that it required about 3.4 lbs. of feed to produce one pound of eggs, versus the current situation, where 2 lbs. of feed produces about 2 lbs. of eggs. That’s how the 42% difference is calculated.

Q. How has such a huge increase occurred?

Prof. Xin: There are a number of factors. The birds in production these days are actually lighter on average, so they need less feed. Genetics, of course, are also important, perhaps the primary factor.

Q. Does the fact that birds have been bred to be lighter affect welfare?

Prof. Xin: No, not really. The lighter average weights don’t impact welfare; that’s a different issue altogether.

Q. You also noted that egg discard rate was 75% less in 2010. That is huge. Why?

Prof. Xin: Part of the answer, we believe, is due to improved handling, better automation. That’s what the literature from back then suggests. Also, nutrition could be a factor, as well. Proper nutrition is critical for producing strong eggshells, and that could likely be a factor, too.

Q. Finally, you stated that chicken mortality has decreased by 57% over the last 50 years. Why such a dramatic decline?

Prof. Xin: Yes, that is indeed a dramatic difference. There are several reasons. First of all, through better genetics, laying hens are more resistant to disease. Second, we have better vaccines to prevent avian diseases. And there is a so much better control, in terms of biosecurity and also simply by providing a much more environmental control. Heat stress—and cold—have an impact on health, and that’s proven by the mortality statistics.

Q. Finally, let me ask the key question: Given the tremendous gains in efficiency over the past 50 years, what does the future hold? Can we expect continued improvements going forward?

Prof. Xin: Yes, I believe there are still opportunities to improve efficiency. With [farmed] fish, you can produce one pound of protein for one pound of feed, and with continued genetic and nutritional improvements, I believe the egg industry can approach that standard.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.