Samples of pelleted feed may be taken during manufacturing and analyzed for nutrient content in order to estimate if nutrients are in accordance with diet formulation. The objective of this study was to determine the impact of mix time, sample location, sample number, and sample blending technique on analyzed nutrients. Ingredients were mixed in a single screw vertical mixer for 30 s or 10 minutes. Samples were taken post extrusion from the pellet die as hot pellets or post cooling and conveyance as finished feed. Two or 10 samples were collected at equally spaced time intervals and pooled. Subsamples were obtained by blending pooled samples by hand or using a sample splitting device. Proximate and supplemental amino acid analysis was determined on each blended subsample and standardized for moisture content. Crude fat and free supplemental DL-methionine were affected by mix time (P < 0.05). The 10-minute mix time produced crude fat and free supplemental DL-methionine that had lower and higher values, respectively, compared to the 30-second mix time and agreed more with the calculated nutrient profile and diet formulation. Free supplemental DL-methionine was also affected by sampling location (P < 0.05). Samples obtained at the pellet die were higher and agreed more with diet formulation compared to finished feed samples. Analysis of free supplemental DL-methionine from samples obtained at the pellet die may best indicate pelleted diet homogeneity and validate the diet formulation.