I put all skins with feathers (I skin, not pluck), feet, wings, guts and head in my garden covered with a layer of either sheep poo and old
hay or chicken poo and bedding or garden soil or
wood chips and with a small cairn of rocks on top to keep the raccoons from digging it up. Seems to
compost quite rapidly. I butcher one chicken every week or so, and I'm able to put a new "grave" in a different spot, so I just move the rocks from one place to another. Eventually I might have a more formal way of composting these items, but for now this is easy.