How to Compost Chicken Manure Safely in New Zealand

Updated June 2026

Turn coop bedding into the best free fertiliser you will ever use, the safe way

A backyard flock gives you eggs, but it also gives you something almost as valuable, which is a steady supply of one of the richest garden fertilisers around. The catch is that fresh chicken manure is too strong, and too risky, to use straight on your plants. Composted properly, that same manure becomes dark, crumbly, plant-safe gold that feeds your beds for free.

This guide is specifically about chicken manure. For everyday kitchen and garden composting, see our general composting guide. Here we focus on why raw poultry manure is too hot to use, how to compost and age it safely, the deep litter method in the coop, the simple carbon to nitrogen balance, and how to tell when it is ready. Use the calculator below to see roughly how much manure and finished compost your own flock will make in a year.

Why Raw Chicken Manure Is Too Hot to Use

Gardeners call fresh chicken manure hot, and they do not mean the temperature. They mean its chemistry. Chicken manure is one of the most nitrogen-rich animal manures you can get, and much of that nitrogen quickly converts to ammonia. Spread raw on a growing bed, it delivers far more nitrogen and ammonia than plants can cope with. The result is scorched roots, burnt leaf edges and yellowing, the opposite of the lush growth you wanted.

There is a second, more important reason never to use it fresh on anything you eat. Raw poultry manure can carry pathogens, including Salmonella and E. coli. Putting it on lettuce, herbs or any crop you harvest soon after is a genuine food-safety risk. Composting solves both problems at once. It tempers the nitrogen down to a balanced level, and a properly hot, well-managed compost process reduces those pathogens to safe levels.

Manure Compost Calculator

Enter how many laying hens you keep and this tool estimates how much fresh manure they produce in a year, the carbon bedding to mix with it, and roughly how much finished compost you can expect. The figures are approximate, based on a laying hen producing around 0.1 kg of fresh manure a day, about 36 kg a year. Real output varies with breed, diet and how much bedding you collect.

How to Compost Chicken Manure Safely

The whole job comes down to mixing the strong, wet, nitrogen-rich manure with plenty of dry, carbon-rich material, getting the pile hot, then giving it time to mellow.

1. Mix in plenty of carbon

Manure on its own packs down into a wet, smelly, airless mass that will not compost well. Mix it with carbon-rich browns such as straw, dry autumn leaves, shredded paper or cardboard, and wood shavings. Most of this comes free with the job, because the coop bedding you rake out is already mostly carbon. Aim for roughly two parts carbon material to one part manure by volume.

2. Get it hot

Build the pile at least a cubic metre in size so it can hold heat, keep it as damp as a wrung-out sponge, and let it heat up. A well-built pile reaches 55 to 65 degrees Celsius in the active phase, which is the temperature range that breaks material down fast and reduces pathogens. Turn the pile every week or two to bring the outside into the hot centre and add air. It will reheat after each turn while there is fresh material to work on.

3. Age and cure it

The hot phase is only the start. Once the pile stops reheating after turning, let it cure and age for several more months. This curing time is when the harshness mellows out and the compost finishes into something gentle enough for any plant. From fresh manure to finished, plan on about 6 to 12 months, or until it passes a proper hot-compost process and smells earthy rather than of ammonia.

The Deep Litter Method in the Coop

Deep litter is composting that happens inside the coop, with the birds doing much of the work. Instead of cleaning the floor out constantly, you start with a thick layer of carbon bedding such as wood shavings, straw or dry leaves, then keep topping it up over the season. The chickens scratch and turn it as they forage, mixing droppings through the carbon, and a slow compost process develops in the litter itself.

Done well, deep litter stays surprisingly dry and low in smell, keeps the coop warmer in winter, and means less work for you. Keep adding fresh carbon whenever it looks damp or starts to smell, make sure the coop is dry and well ventilated, and once or twice a year remove the well-broken-down lower layer to finish off in your outdoor compost pile. It is the laziest, and one of the best, ways to turn a flock into fertiliser.

The Carbon to Nitrogen Balance, Made Simple

Every compost pile is a balance of two kinds of material. Greens are wet and nitrogen-rich, and chicken manure is about as green as it gets. Browns are dry and carbon-rich, like straw, leaves, paper and shavings. Composters talk about the carbon to nitrogen ratio, written as C:N. A pile that breaks down well sits in the rough range of 25 to 30 parts carbon to 1 part nitrogen.

You do not need to do any maths. The practical rule is simple. Because chicken manure is so nitrogen-heavy, you mix in roughly twice as much carbon bedding by volume to bring the balance right. Too much manure and the pile turns into a wet, ammonia-smelling sludge. Too much carbon and it just sits there and barely heats. Aim for damp, well mixed, and earthy-smelling, and adjust by feel.

How to Tell When It Is Ready, and How to Use It

Finished chicken manure compost looks and smells nothing like what you started with. It is dark brown to almost black, crumbly and even in texture, cooled to roughly air temperature, and it smells earthy and sweet like good forest soil. The original straw, shavings or leaves have broken down so far you can no longer pick them out. If it still smells sharp or of ammonia, still feels warm in the middle, or still shows recognisable bedding, it needs more time.

New Zealand Seasonal Note

New Zealand runs on southern-hemisphere seasons, and that shapes how fast your manure pile works. A heap built in the warmth of summer (December to February) heats up and powers through its active phase quickly, so manure started early in summer can be well on its way by autumn. Over a cool, wet winter (June to August), the same pile slows right down and may sit nearly dormant until things warm again.

To keep things moving year round, build or turn your bigger piles in the warmer months, cover the heap to keep heavy winter rain from drowning it, and make piles large enough to hold their own heat. In the colder south, expect the whole process to sit at the longer end of that 6 to 12 month range, while the warm north moves faster. For timing tuned to your exact spot, use Find My Region or open the Planting Season app.

Frequently Asked Questions

See also: Composting Guide and Poultry