Animal waste is a potential pollution hazard as it can harbour contaminants, such as antimicrobial residues, mycotoxins, and pesticides, becoming a risk to the public, animal, and environmental health. To assess this risk, 15 experimental broiler chickens orally received contaminants to evaluate excretion levels. An analytical method was previously developed to detect 18 substances in poultry droppings using high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). Contaminants including tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, chlortetracycline, 4-epi-chlortetracycline, tylosin, erythromycin, enrofloxacin, ciprofloxacin, flumequine, florfenicol, sulfachloropyridazine, sulfadiazine, 2,4-dichlorophenoxyacetic acid, zearalenone, alpha- and beta-zearalenol, were extracted with EDTA-McIlvain and acetonitrile. This method showed a p-value < 0.05, RSD < 25%, and R2 > 0.95 in the calibration curves linearity for all analytes. The limit of quantification, selectivity, decision limit for confirmation, matrix effect, precision, and recovery parameters were validated according to European Union document 2021/808/EC, technical report CEN/TR 16059, SANTE/11813/2017 and according to the Veterinary International Conference on Harmonization: VICH GL2 and GL49. This method confirmed the detection of most analytes 12-36 h post-administration and simultaneously detected and quantified mixed contaminants. Thereby, poultry droppings are a potential matrix for spreading contaminants in animal production before slaughter and their control will minimize environmental impacts and mitigate antimicrobial resistance.