What breed of chicken is the most common for commercial egg production?

The White Leghorn is the breed most commonly associated with commercial egg production. It is a lightweight, highly efficient layer that produces many large white eggs while consuming relatively little feed.

Leghorns originated in Italy and were developed into a standardized breed after reaching Britain and the United States during the 19th century. Their name comes from Livorno, the Italian port known in English as Leghorn. White Leghorns became especially important to modern egg farming because their white plumage, active nature, small body, and exceptional laying ability suited intensive production.

Commercial farms often use specialized hybrid strains rather than traditional purebred birds. Many of those hybrids descend from or were developed using White Leghorn genetics, so “White Leghorn” is the standard breed answer even when the birds themselves carry commercial strain names. Brown-egg layers may be equally productive, but they generally require more feed because they are larger-bodied.