Researchers tested whether mushroom mycelium (the root structure of mushrooms) grown in large bioreactors could be used as a supplement in chicken feed as a sustainable alternative to traditional ingredients. Over 5 weeks, broilers received feed with 0%, 2.5%, or 5% mushroom mycelium, with no negative effects on growth, digestion, or overall health observed. The study suggests that this biotechnologically produced mushroom biomass is a safe and potentially sustainable feed ingredient for poultry production.