Chickens as a Waste Disposal System

Victor Luca, 26-Oct-20.

The Beacon 16-Dec-20

Jack Karetai-Barrett holding eggs from the family’s back yard chooks. Dog George Woof keeps a watchful eye on things.


The world produces about 4 billion metric tonnes of food per annum. This food is not distributed evenly with some countries experiencing food gluts while others are unable to even feed their populations. In 2016 about one billion people were considered by the Food and Agriculture Organization of the United Nations to be malnourished. In the United States in 1995 about 27% of edible food was wasted. This just doesn’t seem right does it?


Food waste can be defined as the amount of food material produced and ultimately discarded during any stage of the food supply chain.


In Australia for example an estimated 7.5 million tonnes of food waste is generated annually and this is generally disposed of in landfills. In these facilities, the waste is decomposed anaerobically generating methane, a greenhouse gas that is between 25 and 30 times more potent than carbon dioxide. Food waste going to landfills therefore causes, not just an economic loss, but also a negative environmental impact. Presently, food loss and food waste account for about 6% of global greenhouse gas emissions.


The diversion of food waste from landfills, increased food donations, and avoidance or reduction of food waste within the supply chain are things that we should be strongly encouraging. In many societies methods other than landfills are sought for dealing with food waste. California for instance has 26 composting facilities for food wastes. Whilst these facilities can anaerobically decompose food waste, significant amounts of greenhouse gases can be generated from such facilities.


Aerobic composting is superior to anaerobic composting because it does not produce methane since methane-producing microbes are not active in the presence of oxygen. Aerobic composting is one method to reduce methane emissions from organic waste currently stockpiled or sent to landfill. Composting practices that minimize anaerobic conditions and maximize aerobic conditions will be the most effective at reducing greenhouse gas emissions. Aerobic microbes convert the inputs into stabilized carbon for the soil, with by-products of heat, carbon dioxide and water.


About 700,000 tonnes of organic waste material was composted in Western Australia in 2012. The composite that is produced can be used as a soil amendment and therefore improve the capacity of land to grow more food. Composting on an industrial scale however is not as simple as it sounds as multiple steps are involved (some labor intensive) and the conditions need to be closely monitored and controlled in order to obtain the correct balance of carbon- and nitrogen-rich materials. Those that have bought a bag of composite from say Bunnings know that this waste product is not cheap to buy.

So is there a more efficient and simpler means of dealing with food waste?

Enter the humble chook. The chook, like all birds, is a descendent of the dinosaurs. Poultry is a prominent part of the livestock produced in the world.


Meat production on protein basis for different regions of the world. Source: http://www.fao.org/gleam/results/en/


So although the dinosaurs are gone, we have become very dependent on their descendants for our nutritional requirements.


Chooks are in such high demand because they are hardy creatures that grow relatively fast in most areas of the world. The virtues of chooks may however go way beyond their nutritional value. In fact, we can add food recycling to the list of virtues that backyard chooks can bring to their communities, by reducing the volume of unwanted food going into landfills.


Austin, Texas recognized their value when they pioneered a zero-waste program where they pay citizens to keep backyard chickens. The goal of the program is to reduce the food entering landfills by redirecting it to backyard chickens.

Whilst unwanted food going to landfills creates methane, unwanted food fed to backyard chooks creates fresh eggs, a potent source of protein and other goodies (see table) without significant generation of green-house gases.

Nutritional content of one 44 g egg. Source: https://fdc.nal.usda.gov


Name Content %DV

Total lipid (fat) 4 g 6%

Carbohydrate, by difference 0 g

Calcium, Ca 19.8 mg 2%

Iron, Fe 0.722 mg 4%

Sodium, Na 59.8 mg 3%

Vitamin C, total ascorbic acid 0 mg

Vitamin A, IU 200 IU 4%

Fatty acids, total saturated 1.5 g 8%

Fatty acids, total trans 0 g

Cholesterol 165 mg 55%


Those readers concerned about the cholesterol content of eggs should fear not because according to the NZ Heart Foundation “while egg yolks are high in cholesterol, it is saturated fatty acids that have a greater effect on our blood cholesterol levels”. Although the relationship between cholesterol and heart disease has long been controversial, the most current scientific studies suggest that dietary cholesterol is not the villain we once thought it was and that raising dietary cholesterol levels has no influence on coronary heart disease. Therefore eating one egg per day does not have any material impact on the risk of cardiovascular disease or strokes.


Backyard chickens can live up to five years but they can go into the pot well before that. And lest we forget, during their lifetimes chooks also produce a valuable fertilizer for the backyard garden.


A backyard chook can consume approximately 0.7 Kg of household food scraps per week, or approximately 38 Kg per year. A flock of four backyard chooks would be expected to consume approximately 151 Kg of household food scraps per year, about as much as the average food wasted by each person in New Zealand each year.

Chooks can even be used to convert food scraps to useful food in an active community composting system.

Right: Backyard chickens feeding on food scraps from a composite pile. Source: Black Dirt Farms, Feeding Community Food Scraps to Laying Hens in an Active Composting System, March 2017. Left: Single-comb White Leghorn hens housed for egg production in a multitiered layer house. Source: https://www.britannica.com/topic/poultry-farming


There are some other good reasons for maintaining a small healthy flock of backyard chooks. For instance those concerned about animal cruelty should consider how much happier the average backyard chook must be compared to battery hens cooped up in small cages in factory farming systems.


But it is not just a matter of cruelty that should concern us. These intensive factory farms can be a source of disease and perhaps even the next pandemic. To avert disease and to fatten the chickens in these cramped and stressful conditions, the poultry industry has for decades used low doses of human antibiotics. In these cramped and stressful factory conditions, the chooks can harbor bacteria that become resistant to the antibiotics that they are fed and so potentially give rise to a public health problem.

Many countries have birds as their national symbols. New Zealand for instance has the Kiwi, the United States has the Bald Eagle and the United Kingdom has the Robin. But only France has a bird that can be used as both food source and municipal food waste disposal system.


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