I would check with the processing plant. There is a local meat packer here who sells raw food food for pets, you can get carcasses, backs, wings, necks (chicken, turkey, lamb, or pork), or ground trim/bones/organs, recreational bones, organs... lots of stuff that would otherwise probably be largely wasted for them. Even if the plant in your area doesn't start an official program, I bet you could set something up individually to "take that stuff off their hands" inexpensively.