Chicken Platelet-Derived Growth Factor-BB (PDGF-BB) is a homodimeric growth factor composed of two PDGF-B chains that plays an important role in cell proliferation, migration, angiogenesis, and tissue repair in chickens (Gallus gallus). PDGF-BB signals primarily through platelet-derived growth factor receptors (PDGFRs), particularly PDGFR-β and PDGFR-α/β complexes, activating downstream signaling pathways such as PI3K/AKT, MAPK, and STAT that regulate fibroblast proliferation, smooth muscle cell growth, and extracellular matrix production. In chickens, PDGF-BB is produced by platelets, macrophages, endothelial cells, and fibroblasts, and is released during tissue injury, inflammation, and wound healing. It contributes to vascular development, connective tissue formation, and dermal repair, supporting regeneration of damaged tissues following infection or injury. PDGF-BB signaling is also involved in bone development and skeletal growth in avian species, where it influences osteoblast activity and extracellular matrix deposition. Additionally, PDGF-BB may participate in fibrotic and inflammatory responses during chronic tissue injury. As a regulator of cell growth, angiogenesis, and tissue remodeling, chicken PDGF-BB is important for studies of avian development, wound healing, skeletal biology, and host responses to injury, supporting research relevant to poultry health and production.