Abstract
The rising demand for white meat has led to an increased reliance on intensive farming systems involving high stocking density that can cause stress on birds, hinder their growth and behavior, and reduce profitability. This necessitates the use of antioxidant growth enhancers to mitigate the impact of stress. In response to this challenge, this study aimed to determine the effectiveness of natural growth promoters compared to antibiotics in alleviating the negative impact of stocking density stress by conducting an experiment using 300 one-day-old Cobb 500 chicks over 35 days. After 7 days of acclimatization, the chicks were weighed, wing-tagged, and divided into five groups with 60 chicks each, divided into three replicates of 20 birds. The groups were categorized as follows: low stocking density (LSD) with 10 birds/m2, high stocking density (HSD) with 18 birds/m2, HSD+AGP feeding diet with 55 ppm/kg feed Bacitracin Methylene Disalicylate (BMD-50; Zoetis Products, Chicago Heights, IL, USA) as antibiotic growth promoter, HSD+LPEM with a low concentration of aqueous plant extracts mixture (LPEM) (8 ml fennel + 8 ml fenugreek + 8 ml thyme/L of drinking water), and HSD+HPEM with a high concentration of aqueous plant extracts mixture (HPEM) (10 ml fennel + 10 ml fenugreek + 10 ml thyme/L of drinking water). The findings revealed that HSD led to a decline in productivity, behavior, and economic efficiency when compared to LSD. AGP improved these aspects but at a lower level than PEM. In conclusion, to ensure the production of antibiotic-free meat, decrease antibiotic resistance, and achieve better behavioral, productive, and economic outcomes, it is proposed to use a combination of fennel, fenugreek, and thyme aqueous extracts in PEM at a concentration of 8 or 10 mL/L in the drinking water. However, for an optimal cost-benefit ratio, it is recommended to utilize PEM at a concentration of 10 mL per liter of the bird's drinking water.

Key words: HSD, AGP, PEM, fennel, fenugreek, thyme.