Abstract Even the highest quality ingredients undergo oxidative stresses during manufacturing processes, increasing the nutrition delivery challenges facing large-scale feed manufacturing. In this study we investigate the impact of increasing peroxide values (PV) in the chemical composition in rendered chicken meal (CM) and chicken by-product meal (CB). To determine canine acceptance, working Labrador Retrievers (20 male; 20 female) were used in a preliminary novel aromatic palatability test as well as a traditional two-pan palatability test. PV sample levels ranged from < 10-200 (CB or CM Sample identification: 1.~ < 10, 2.~20-50, 3.~50-100, 4.~100-200). Results indicate that dogs preferred reduced peroxide values in both aromatic (p= < 0.05) and traditional 2-pan palatability trials (p= < 0.05). Preference testing results correlated with extensive physical and chemical data obtained using a Heracles Electronic Nose ultra-fast gas chromatography (UFGC), solid-phase micro-extraction (SPME), and gas chromatography-mass spectrometry (GC-MS). The broad-spectrum analysis utilized solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) to identify 177 nonpolar compounds, 340 polar compounds, and 457 volatile compounds. The overall composition did not vary; however, individual compounds had strong linear correlations with peroxide value. In chicken by-product meal samples, 38 compounds were linearly correlated; in chicken meals, 27 compounds were identified (r2>0.90). These data: 1) introduces novel quality control markers for further research and showcases the potential for greater accuracy by developing product specific markers; 2) confirms that the chemical differentiation between peroxide values went beyond lipid oxidation and highlighted multiple compounds of interest for further study; and 3) emphasizes greater levels of peroxide in pet foods have unfavorable palatability. This research was funded by the Fats and Protein Research Foundation.