Particle breakage is a common phenomenon during the processes of production, storage, and transportation. Because of the requirements for pellet integrity in poultry farming, research on the breakage characteristics of feed pellets is necessary. In this paper, repeated compression tests under different loading forces and repeated impact tests under different air pressures were carried out with feed pellets as the research object. The breakage behaviors were described, and the particle size distribution of feed pellets was analyzed quantitatively. The results revealed a positive correlation between crack density in feed particle beds and loading force. The compression process was divided into three stages based on force–displacement curves. The size of the feed pellets during repeated impacts decreased continuously and was negatively correlated with air pressure. The Weibull function accurately described the particle size distribution, with R² values exceeding 0.97 and 0.96. The Weibull parameters showed a steady breakage degree in compression tests and a growing breakage degree in impact tests. The variation in energy and pulverization rate under different loading conditions was examined as the number of loading cycles increased. The relationship between energy and pulverization rates was fitted, showing that both parameters increased with loading cycles in different loading methods. The model of Vogel and Peukert could describe the relationship between energy and pulverization rate well, with R² values exceeding 0.94. The minimum energy required for pellet breakage was higher in compression than in impact due to the compaction of the feed particle bed during repeated compression. The results can provide basic theory and data support for breakage characteristics and quality evaluation of feed pellets.

The hammer mill is widely employed in various industrial sectors for crushing processes; however, its performance is often hindered by low grinding efficiency and high energy consumption. In this study, the discrete element method was used to investigate the crushing process of maize kernels within a hammer mill system. A comprehensive investigation was conducted to examine the influence of varying ruminant structures on particle circulation patterns. Quantitative assessment of crushing efficiency was performed through particle mass throughput and median particle size (D50), while screening efficiency was evaluated using damage degree index, collision frequency, and collision intensity under different ruminant structures. The findings reveal that the circulation motion of maize particles within the hammer mill significantly hinders both crushing and screening efficiency. Comparative analysis indicates that both conventional rumination troughs and the newly proposed rumination arch effectively disrupt the particle circulation motion. Quantitative analysis reveals that both the ruminant trough and the ruminant arch improve the crushing efficiency of the hammer mill. Specifically, the ruminant arch enhances crushing efficiency by 13.26% and the average particle size distribution by 5.78% compared to the ruminant trough. Moreover, both the ruminant trough and the ruminant arch contribute to improved screening efficiency in the hammer mill. When compared to the ruminant trough, the ruminant arch increases the damage degree to the particle circulation layer by 21.29%, the collision frequency by 24.62%, and the collision intensity by 18.97%. This study provides a novel approach for improving both the crushing and screening performance of hammer mills, offering insights for future optimization in industrial milling applications.