How did the time needed to raise broiler chickens change during the 20th century?

During the 20th century, the time required to raise broiler chickens to market weight decreased significantly due to advancements in poultry breeding, intensive nutritional research, and improved management practices.1

In the mid-20th century, it took approximately four months for a broiler chicken to reach a market weight of 2.3 kg (5 pounds). By contrast, modern broiler chicks can reach that same 2.3-kg market weight in just five weeks. This dramatic reduction in production time is the result of applying genetic principles—such as inbreeding and crossbreeding to maximize heterosis—alongside scientific disease control and highly optimized feeding programs.12