Some scavengers can speed up the composting process by converting organic matter (food) into manure. Manure tends to have a high nitrogen content, moisture, smaller fragments that break down quickly and microorganisms. Good scavengers for the backyard composting include pigeons, rabbits and chickens. Pigeons eat seeds and produce manure with a very high nitrogen content. Rabbits chew on sticks to sharpen their teeth and eat plant material. They can process both kitchen scraps and most yard wastes. Their dung can be used directly in the garden, but their urine needs to be processed in the compost pile to avoid burning plants. When I have rabbits, I train them to use litter boxes filled with organic litter. The used litter makes an excellent addition to my compost piles.
Chickens are omnivores. They eat insects, mice, arachnids, kitchen scraps, greens, fruits, seeds, etc. They produce manure that increases the nitrogen content of compost. Chickens also do a good job of digging through the compost and turning it for you.
Hens provide a bonus of eggs for breakfast.