Maybe it's time to give the 20 billion chickens on our beleaguered planet a little more respect and a lot more love. The meat du jour for Americans was once the royal bird of Egypt and a key influence on Charles Darwin's theory of evolution. Its egg supplies the key ingredient in our flu vaccines, and its protein and vitamins are the nutritional margins against malnutrition among the world's rural poor. Chickens also have mental abilities similar to humans (well, some humans, anyway) that include understanding geometry, adding and subtracting and a "primitive self-consciousness" that proves that they "know they exist and, therefore, suffer."

And suffer they do. As science writer Andrew Lawler investigates so ably in "Why Did the Chicken Cross the World?" we treat our feathered friends so poorly that the chicken is not even worthy of official animal status by our government and is therefore exempt from the merest of animal welfare laws.

Overseas conditions are not much better. In the Philippines, some 15 million roosters die annually from cockfights in venues such as the World Slasher Cup.

In the United States, overcrowded conditions in claustrophobic battery cages without roosting perches or natural light include practices in which the tips of chickens' beaks — the bird's "primary sense organ" — are sheared off to prevent injury. Colorado animal scientist Temple Grandin said chickens are bred to "grow at the far limits of what is biologically possible."

Thus, those ginormous chicken breasts for sale at the grocery store.

More than half of the 250,000 workers in poultry slaughterhouses are women, and 50 percent are Latino. Lawler reports that the work is "ugly, low-paid, and dangerous."

Andrew Lawler

The treatment of — and our disconnect from — chickens are not the main narrative engines of Lawler's book, but they might linger longer in memory than the author's meticulous research of the chicken's ancestral roots that began as a wild red jungle fowl in South Asia and then, over thousands of years, evolved to today's domesticated barnyard chicken. Along the way the chicken has accompanied us on each stage of our journey from primitivism to modernism, carried in baskets across mountains, ferried in dugout canoes down rivers and across oceans and hauled in oxcarts across major trade routes.

Lawler is convincing when he concludes that we are more like the chicken than we might admit, "gentle and violent, calm and agitated, graceful and awkward, aspiring to fly but still bound to earth."

Stephen J. Lyons is the author of three books. His next book, "Going Driftless," will be published in May 2015. He lives in Illinois.