Chicken and Turkey Transforming Growth Factor Alpha (TGF-α) is a member of the epidermal growth factor (EGF) family of growth factors, which also includes epidermal growth factor (EGF), amphiregulin, betacellulin, epiregulin, and heparin-binding EGF-like growth factor (HB-EGF). In both chickens (Gallus gallus) and turkeys (Meleagris gallopavo), the TGF-α protein is identical at the amino acid level, indicating strong evolutionary conservation and suggesting similar biological functions in these avian species. TGF-α is initially synthesized as a membrane-anchored precursor that is proteolytically cleaved to release a soluble ligand that binds the epidermal growth factor receptor (EGFR/ErbB1). Activation of EGFR stimulates intracellular signaling pathways including MAPK/ERK, PI3K/AKT, and JAK/STAT, which regulate cell proliferation, differentiation, and tissue growth. In chickens and turkeys, TGF-α is expressed in tissues such as the skin, gastrointestinal tract, and developing epithelial tissues, where it contributes to epithelial development, tissue repair, and regulation of cell growth. TGF-α signaling is also involved in avian embryonic development and epithelial tissue regeneration following injury. Because poultry species are widely used in developmental biology, epithelial biology, and agricultural research, characterization of chicken and turkey TGF-α supports studies of EGFR signaling, tissue growth regulation, and conserved growth factor functions in vertebrate development relevant to poultry health and production.