“How old do you think these chickens are?” Levy Phiri asked the crowd, after scooping four multicolored birds out of a crate and setting them down in the courtyard outside the primary school in Kambvumbe, a village in Zambia’s rural Eastern Province.

The roughly 200 people who came out in the midafternoon heat for this presentation held by the country’s largest chicken hatchery and processor craned their necks for a better look.

A year, someone called out. Fourteen months, another suggested.

Mr. Phiri, a field representative for the company, Hybrid Poultry Farm, paused a moment for suspense. They are just six weeks, he revealed. Surprise rippled through the gathering.

These are not just any chickens. They are Zambro chickens, birds specifically bred to thrive in the toughest climates. A dual-purpose chicken — more on that later — that needs less water and feed, grows faster and fatter and lays more eggs. A chicken that is more resistant to disease and costs less to raise than many of the village chickens found in backyard coops.