Extrusion processes for the production of retort-stable feed products comprise forming a mixture of feed ingredients and subjecting the mixture to specific mechanical energy (SME) and specific thermal energy (STE) inputs to achieve low SME/STE ratios, followed by retorting of the extruded products. The extrusion system (20) includes a preconditioner (22), extruder (24), and a two-stage drying assembly (26/28). The extruded products may be retorted directly from the extruder or after partial or complete drying thereof.
