A method for forming a digestible pet chew includes combining ingredients including a leavening agent and an acid to form a mixture having about 16 to 32% moisture, adding the mixture to a barrel of an injection molding machine, and plasticizing the mixture with heat and pressure to form a plasticized material. The plasticized material is then injected into a chilled mold and cooled in the mold for a time sufficient to form a skin surrounding a center portion. The mold is then released to allow the center portion to expand to form a pet chew having an outer skin and an expanded center.
