Chicken EGF (Epidermal Growth Factor) is a growth factor peptide belonging to the EGF family of ligands, which also includes transforming growth factor-α (TGF-α), amphiregulin (AREG), heparin-binding EGF-like growth factor (HB-EGF), betacellulin (BTC), and epiregulin (EREG) that signal through the epidermal growth factor receptor (EGFR/ErbB1) to regulate cell proliferation, differentiation, and tissue repair. In chickens (Gallus gallus), EGF is produced by epithelial cells, fibroblasts, macrophages, and glandular tissues, particularly within the gastrointestinal tract and developing embryonic tissues, where it plays an important role in epithelial development, intestinal growth, and tissue regeneration. Binding of EGF to EGFR activates intracellular signaling pathways such as MAPK/ERK and PI3K–AKT, which promote cell proliferation, survival, and differentiation of epithelial cells. In poultry biology, EGF contributes to maintenance and repair of intestinal epithelium, supporting nutrient absorption and barrier integrity in the digestive tract. Because chickens are widely used as animal models for developmental biology and embryology, chicken EGF has been studied in avian embryo and limb development models, where EGF signaling helps regulate cell proliferation and tissue patterning during embryonic growth, providing insights into growth factor signaling and tissue development across vertebrate species.