Since the molecular mechanism underlying feed efficiency (FE) in slow-growing chickens is poorly understood. Thus, this study aimed to investigate the proteome differences and possible pathways associated with FE in male slow-growing chicken by using a label-free quantitative proteomic approach. At 10 weeks of ages duodenum samples from six animals (three high-FE and three low-FE chickens) were collected for differential abundant proteins (DAPs), protein networks, functional enrichment and pathway analysis. In this study, we found 40 DAPs significantly associated with FE pathways included glycolysis/gluconeogenesis, peroxisome, oxidative phosphorylation, tight junction, and cysteine and methionine metabolism. Thus, the differences of protein driving those pathways affected the FE potential of slow-growing chicken might be interesting candidate biomarkers for genomic selection of animals with a higher efficient feed utilization.