Medicinal plants are gaining attention as natural alternatives to chemical additives in poultry production. This study evaluated the antioxidant and anticoccidial activities of both aqueous (AQ) and hydromethanolic (HM) extracts of Mentha aquatica (ME), Rosmarinus officinalis (RO), and Thymus algeriensis (TH). In vitro assays were conducted against Eimeria oocysts, while in vivo trials involved 450 Cobb 500 broiler chicks randomly distributed into nine groups, including untreated and infected controls, more specifically, a group treated with Toltrazuril, and six groups treated with plant extracts at two concentrations (15 and 25 mL/L in drinking water). Administration began on day 7, and all animals except uninfected controls were inoculated orally with 10,000 sporulated Eimeria oocysts on day 10. Growth performance, feed efficiency, oocyst output, lesion scores, and histopathological changes were assessed until day 32. HM extracts showed higher antioxidant activity, particularly ME-HM. RO-HM, which demonstrated the strongest in vitro anticoccidial effect. The in vivo results revealed that TH-AQ and RO-AQ significantly improved body weight, feed conversion efficiency, and intestinal integrity. Anticoccidial indices (ACI) confirmed their efficacy, with values exceeding 180 for TH and RO, indicating excellent anticoccidial activity comparable to that of Toltrazuril. These findings support the potential of these phytogenic extracts as practical natural tools in poultry health management.