At a 93,000-square-foot warehouse-office in San Francisco’s Mission District, they’re growing chicken. Not chicken the animal—chicken the protein.

Just Inc., the maker of plant-based mayonnaise and vegan eggs, is using cellular agriculture to take extracted animal cells and turn them into chicken nuggets. Technicians grow the cells (the company’s catalog includes both stem cells and not) in baths of nutrient-rich liquid media, a bespoke “feed” that includes salts, sugars, amino acids, and often, notably, no animal molecules at all. Just is turning huge bioreactors into mini chicken farms, getting cells to multiply naturally, without an animal body to house them.