Cellulitis in poultry is an acute, subcutaneous bacterial infection, primarily caused by Escherichia coli, characterized by diffuse inflammation, yellowish skin discoloration, and subcutaneous fibronecrotic plaques. Lesions are most commonly observed in the abdomen and thighs, occasionally extending to the breast, back, or legs, and may include petechiae and exudates of varying color. The condition is typically initiated by skin trauma, which allows bacterial entry, and is exacerbated by factors such as rapid growth, high stocking density, poor litter quality, and immunosuppression. Although affected birds often appear clinically normal, lesions are readily detected postmortem, contributing significantly to carcass condemnation and economic losses. Other bacterial species, including Pseudomonas aeruginosa, Proteus vulgaris, Enterobacter agglomerans, and Staphylococcus aureus, may also be involved. Early detection on-farm, along with good management practices and stress reduction, is crucial for minimizing lesion development, reducing condemnations, and improving poultry health and welfare.