The chickens squawking in a cinder-block barn near the heart of the Virginia Tech campus in Blacksburg, Va., don’t know it, but they play an important part in the plans of the agriculture industry. The challenge: How to feed the 2.4 billion additional people expected to join the global population by 2050.

Unlike the roughly 60 billion chickens world-wide now slaughtered for meat each year, these birds are raised for their DNA. Paul Siegel, professor emeritus of animal and poultry sciences, studies how their genes influence...