Published 2026-09-05 · data 2018 · Domestic poultry vs wild birds
Chickens now outweigh wild birds
Add up the mass of every bird. Farmed poultry — almost all chickens — are about three times the wild flock. The sky is not the census.
Add up the mass of every bird alive and you get about 7 million tonnes of carbon. Farmed poultry — almost all of it chickens — hold 71% of that; every wild species on Earth combined holds just 29%. The 2018 global biomass census found the coop now outweighs the wild flock.
1 cell = 7,000 tonnes of carbon in birds (0.1% of bird biomass) · 1,000 cells
Context
The figures come from Bar-On, Phillips, and Milo's 2018 PNAS paper 'The biomass distribution on Earth,' which tallied the carbon mass of life on Earth. It estimated domesticated poultry at about 0.005 gigatonnes of carbon and all wild birds at about 0.002 Gt C — the 71/29 split shown here, out of roughly 7 million tonnes of carbon in birds.
The wild share covers every free-living species, from songbirds to seabirds to raptors, while the farmed share rests on birds bred for meat and eggs and continually restocked. That standing poultry stock is a direct artifact of human demand, which is why it can outweigh the entire wild flock.
The measure is mass, not headcount: the comparison is in tonnes of carbon, the study's common currency for all living things. And it is a snapshot compiled for the 2018 paper, not a live census.
Bar-On, Phillips, and Milo, The biomass distribution on Earth, PNAS 2018: domesticated poultry ≈0.005 Gt C; wild birds ≈0.002 Gt C. About 71% / 29% of that combined mass. Cells rounded to 1,000.
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