Chicken Stem Cell Factor (SCF) (also known as KIT ligand, KITLG, mast cell growth factor, or steel factor) is a cytokine and growth factor involved in hematopoiesis, stem cell maintenance, and immune cell development in chickens (Gallus gallus). SCF belongs to a group of hematopoietic growth factors that regulate the survival, proliferation, and differentiation of stem and progenitor cells. It functions by binding to its receptor c-Kit (CD117), a receptor tyrosine kinase expressed on hematopoietic stem cells, mast cells, melanocyte precursors, and germ cells, triggering intracellular signaling pathways including PI3K/AKT, MAPK, and JAK/STAT that promote cell survival and growth. In chickens, SCF is produced by stromal cells, fibroblasts, endothelial cells, and epithelial cells, and can exist in both membrane-bound and soluble forms, enabling both localized and systemic regulation of c-Kit–expressing cells. Chicken SCF contributes to bone marrow and thymic hematopoiesis, immune cell development, pigmentation, and germ cell development during embryogenesis and growth. Because chickens are important models for avian immunology, developmental biology, and hematopoietic research, characterization of chicken SCF supports studies of stem cell regulation, immune system development, and conserved growth factor signaling pathways relevant to both poultry health and vertebrate biology.