Short answers, pulled from the story.
Chicken is the most common type of poultry in the world. The United Nations estimated there were 19 billion chickens on Earth in 2011, outnumbering humans more than two to one.
The modern chicken descends from red junglefowl hybrids crossed with grey junglefowl, first raised thousands of years ago in the northern parts of the Indian subcontinent. Chicken as a meat has been depicted in Babylonian carvings from around 600 BC.
In 1996, European consumption of chicken overtook that of beef and veal, linked to consumer awareness of bovine spongiform encephalopathy, commonly known as mad cow disease.
Roxarsone is an organoarsenic feed additive used in factory farming to control stomach pathogens and promote growth in chickens. A 2013 Johns Hopkins School of Public Health study found that 70% of U.S. chicken samples from producers that allowed roxarsone exceeded FDA inorganic arsenic safety limits. FDA approval for roxarsone and two other arsenic poultry drugs was voluntarily withdrawn by manufacturers in September 2013, and the final arsenic drug, nitarsone, was banned at the end of 2015.
More than 25% of retail chicken in the United States is resistant to five or more different classes of antibiotic treatment drugs, according to the FDA. An estimated 90 to 100% of conventional chicken contains at least one form of antibiotic-resistant microorganism, while organic chicken has a lower incidence at 84%.
The U.S. Department of Health and Human Services recommends a minimum cooking temperature of 165 degrees Fahrenheit for chicken to prevent foodborne illness from bacteria and parasites including Salmonella.