<p>The extensive application of pesticides and insecticides in agriculture has raised significant concerns about their teratogenic effects on non-target organisms, particularly avian species. This study investigated the effects of a combination insecticide containing Chlorpyrifos (50%) and Cypermethrin (5%) on early embryonic development in domestic chick embryos (<i>Gallus domesticus</i>) at a sublethal dose of 0.05&#xa0;µg/egg. Treated embryos displayed several morphological anomalies, including impaired feather development-characterized by reduced feather size and number-alongside limb deformities and eye defects. The research primarily focused on deciphering the disruptions in feather development, a critical component of avian morphology vital for numerous physiological functions. Feather formation is governed by complex signaling pathways, such as Shh, Wnt, BMP, and Notch, essential for proper feather tract formation and patterning. Our findings indicate that exposure to this insecticide combination disrupts these pathways, causing abnormalities in feather bud formation and differentiation. Molecular docking studies demonstrated strong interactions between Chlorpyrifos, Cypermethrin, and key signaling molecules like Noggin and BMP2, suggesting interference with their regulatory functions. Gene and protein expression analyses revealed altered patterns for critical markers, including FGF2, FGF4, WNT5A, SHH, NOTCH1, EDAR, TROY, TWIST-2, and CYCLIN D1, indicating disruptions in cellular proliferation, differentiation, and feather patterning. This study highlights the systemic toxicity and teratogenic potential of Chlorpyrifos and Cypermethrin, underscoring the need for stringent regulatory measures and comprehensive risk assessments to ensure the safe use of these pesticides in agriculture.</p> Graphical Abstract <p></p>