Short answer: The harmattan is the dry, dusty wind that blows off the Sahara from about December to February, sometimes into March. It hurts birds three ways at once: fine dust in the eyes and airways, cold nights that send the flock into piles, and dry air that drives up water intake. Protect the airways first, keep the house warm enough at night without trapping ammonia, and check the drinkers and feeders every morning.
Key takeaways
- Dust is the harmattan's main load. Sweep it out early, before the birds are up and about, and keep feed under lids.
- Cold nights hit the young birds and the flock close to point of lay first. Give them a warmer corner and watch for piles.
- A house closed tight for warmth can gas the flock by dawn. Check the air at bird height before you check the clock.
- Dry air sends birds to the drinkers. A drinker line that kept pace in October can fall behind in January.
- Watery eyes, sneezing and open-mouthed breathing need the vet early, not after a week of waiting.
The morning the haze arrives
The light goes flat and yellow in December. The sun is a pale coin you can look at without squinting, the roof sheets are grey with a fine powder, and a film sits on the water in the drinkers. Then you notice the birds are sneezing, or standing with their eyes half closed, and the day has started with a problem.
Farmers in the south know the harmattan well, but many still treat it as a few cold mornings and a bit of dust. It is more than that. For about three months the air is drier and the dust is finer than at any other time of year, and the birds have to cope with that on top of cold nights and their own growth. A flock that is fine in November can be struggling by the first week of January.
This guide is for the farmer who wants a plan before the haze comes in. It draws on what we see at the hatchery and on what farmers tell us once the dust has settled. The advice is general. Your vet knows your flock, and where a bird is clearly ill, the vet decides what happens next.
What the harmattan actually does to a flock
The harmattan works through three routes, and each one needs its own answer. The first is dust. The wind carries fine particles small enough to reach deep into the airways and the air sacs. Dust also carries bacteria and whatever else is in the air around the farm. It irritates the lining of the eyes and nose, and it gives any respiratory infection a better place to take hold.
The second route is cold. Night temperatures can fall a long way in the dry season, and birds lose heat fast when the air is dry and moving. Cold birds eat more to keep warm, drink more when they can, and put less into growth. Young birds in particular have little reserve, and they show the cold first.
The third route is the dry air itself. It pulls moisture from the birds' breathing passages, and a dried-out lining is less effective at keeping dust and germs out. The same dry air dries the litter at the surface, which lifts more dust every time the birds walk across it. Together the three routes make a house that looks fine from the doorway and is working hard in the background.
Dust, lungs and eyes: protect the airways first
Start with the house, because the birds breathe whatever is in the air around them. Sweep the dust out in the early morning, while the birds are still roosting or settled in their corners, rather than mid-morning when the flock is up and scratching. Sweeping stirs the dust into the breathing zone, so do it gently, wipe the dusty surfaces with a damp cloth, and push the dustiest litter to the edges where birds are less likely to scratch.
Cover the feed. Lidded bins and covered feeders keep the dust off the mash, and you will see birds eat more when their food is clean. Keep the feed store shut when the wind is up. Feed that has picked up dust is not spoiled, but it is less appetising, and a flock picking at dusty feed takes in less of its balanced diet.
Watch the eyes. Watery eyes, crusted lids and a bird that keeps shaking its head are signs the dust is getting to the flock. Wipe the drinkers and the nipples, and check the water line. If the signs spread through the house, that is the moment to call the vet, not the moment to wait and see whether it passes. Respiratory trouble can flare in the harmattan, and our article on chronic respiratory disease in poultry explains the signs and why stress makes them worse. Read it before the season starts.
Cold nights and the birds that feel them most
The birds that feel the harmattan cold first are the chicks in the brooder and any flock that has just moved to a new house. Chicks have little feather cover and little fat, and a chilled chick piles into the corner and smothers the chicks underneath. Our article on preventing chick piling covers the brooder side in detail, so here we focus on the bigger birds.
Broilers in their last three weeks, and layers close to point of lay, are often in open-sided houses. At dawn they sit hunched with feathers fluffed, and they are slow to get up to the feeder. A little warmth in the right place is worth more than a lot of warmth in the middle of the room. Place a few lamps or a heat source at the cold end, check the birds' behaviour at night, and move the lamp if the flock crowds the same corner every evening. Our broiler house setup guide shows how to plan the house layout for this.
Do not chase the thermometer on the wall. Read the flock. Birds spread evenly and drinking normally are comfortable. Birds bunched in one spot, not eating in the morning, or sitting with fluffed feathers at midday are telling you the night was harder than the numbers suggest.
The closed-house trap: warmth that gasses the flock
This is the mistake we hear about most. A farmer sees the cold coming, shuts the curtains tight, seals the gaps and feels pleased with the warm house at night. By dawn the air is heavy with ammonia from the droppings, the eyes are stinging and the birds are gasping. The warmth was real. The air was not.
Warm air rises and collects at the top of the house, and the moisture and ammonia from the litter collect with it. In a sealed house the air does not move, so the birds breathe the same stale air all night. The answer is a small, steady exchange of air high in the house, and cold draught kept off the birds at their level. A house with the vents set high and the curtains shut on the windward side works far better than a house with no air at all.
Use the table below as the night routine. It takes ten minutes, and it is the cheapest protection the harmattan can get.
| Time | What to check | Why it matters |
|---|---|---|
| Before dusk | Feed and water full, drinkers flowing, litter dusty but not caked | Birds should eat and drink before the cold sets in |
| Early evening | Vents set high, curtains shut on the windward side only | Keeps warm, moist air moving out at the top |
| Late night | Birds spread out, no pile in one corner | A pile means a draught or a cold patch where the birds are |
| Dawn | Eye sting when you walk in, smell at bird height, watery eyes | Ammonia peaks before the lights come on, so this is the real test |
| Mid-morning | Litter dust, drinker flow, birds eating normally | Shows whether the night was too cold, too dry or too stale |
Dry air, thirsty birds and the water line
When the air is dry, birds drink more. The moisture they lose through breathing and through the skin has to come back from somewhere, and the drinker is the place. A line that kept up in October can run short by January, especially at the far end, and the birds at the end of the line are the first to show it.
Check the flow at the far end of every line each morning and again around midday. Look for nipples that have lost their pin, bell drinkers that have dropped out of level, and joints that have worked loose in the dry heat. Keep the drinkers at a height where the birds drink without stretching, and make sure the water is clean. Dust settles on the drinker surface first, so wipe the trough or the nipple cup each day. Our water quality guide explains what to look for in the water itself.
Do not add anything to the water on a guess. Some farms use additives in the dry season, but only on a vet's or a nutritionist's advice. Clean, cool, flowing water is still the fix that works on almost every farm.
Feed intake and the appetite that drops
Intake is the number that tells you the harmattan is working. A flock eating less than usual is cold, dusty, sick or short on water, and the answer usually lies in one of those four. Weigh the feed used each day, at the same time, and set the figure beside the previous week. A drop of a few percent for a day is noise. A drop that lasts three days is a warning.
Dusty feed does not get eaten well, so keep the feeder covers on and fill the feeders in smaller, more frequent rounds. Birds that have to scratch through a heap of dust and husk waste more and eat less. Small, frequent fills also keep the feed fresh in the dry air, and feed that dries out loses its appeal faster than most farmers expect. Our feed storage article covers the store side of this.
Ask your nutritionist whether the cold calls for a change in the energy of the ration. Some farms make small adjustments when the nights are long and cold. Do not make a major change without advice, because a sudden change in ration can upset the birds just as the weather is already doing its work.
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Reading the flock: eyes, nostrils and breathing
The first signs of respiratory trouble are small. A bird sits slightly apart from the rest. Its eyes look wet or half closed. It sneezes once, then again. When you walk past, you hear a faint rattle in the air, not just the rustle of feathers. Catch these early and you have a choice. Miss them and you have a flock with a problem that has already spread.
- Watery or crusted eyes, or swelling around the eye or face.
- Discharge from the nostrils, or a bird shaking its head to clear the nose.
- Open-beak breathing, or a bird that keeps its head low while the rest of the flock is up.
- A rattle or wheeze you can hear from the walkway, especially at dawn.
- A drop in feed and water use across a whole section of the house, not just one bird.
When two or more of these show up, call the vet the same day and tell them what you have seen, when it started and what changed in the house. Write it down. The vet will ask for numbers, and numbers are much easier to give if you have been keeping them. Any treatment should come from the vet who has seen the flock, and it should follow the dose and course the vet sets.
What a dusty fortnight costs: a worked example
Say you run 200 layers at a steady rate of laying. A harmattan cold snap and a shut house cut the lay by ten percentage points for ten days. That is 200 hens times 10 percent times 10 days, or 200 eggs that never reached the crate. At 50 GH₵ a crate of 30, those 200 eggs come to about 333 GH₵ in lost sales, before anyone counts the feed the hens ate while they were not laying.
Now add the birds. Suppose two hens die in that fortnight from the chest trouble the dust set off. The eggs are gone, the two birds are gone, and the flock is weaker for the rest of the month. A lidded feeder, a set of vent tubes and an extra ten minutes at dusk cost a small fraction of that.
Numbers like these make the case for the boring jobs: covered feed, a dusted floor, a vent you can open and a walk at dawn. None of them is expensive. All of them are easy to skip on a cold morning.
Planning for the harmattan before it arrives
The best harmattan plan is written in October, when the rains are still falling and the chores feel far away. Check the vent openings and the curtains, repair anything that lets cold air in, and set up a warmer corner for the cold nights. Count the lamps and heat sources you have, test each one, and buy spares before the first dust storm, not during it.
Stock the feed for the dry weeks, but not so much that it sits in the dust for a month. Clean the feeders and drinkers, and make sure the lines are sound. If you are planning chicks for the start of the season, think about the brooder before the box arrives. Our brooder temperature chart shows how the heat should change week by week, and the harmattan nights are when to check it more often. The wider year is laid out in our farming calendar.
If you plan to bring in new birds during the harmattan, order early. Our broiler chick page and layer chick page list what we currently offer, and you can place the order through /#order. If you want to talk through the house before you buy, WhatsApp us on +233 24 915 1503.
A harmattan night checklist you can pin up
- Feed covered, bins shut, and the feeders filled in smaller rounds before dusk.
- Drinkers flowing at the far end, at the right height, and wiped clean.
- Vents set high and open a little, with the windward curtains shut.
- Heat source checked at the cold end, with birds spread evenly by the second hour of dark.
- Eyes, breathing and feed intake checked at dawn before the lights go on.
- Any bird that is apart, hunched or wheezing marked and looked at again at midday.
- Vet called the same day if several birds show respiratory signs.
Questions farmers ask
Does harmattan dust cause disease in chickens?
Dust rarely causes disease on its own, but it irritates the airways and eyes, and it gives germs a foothold. Birds already carrying a respiratory infection often get worse during the harmattan. Keep feed covered, sweep gently, and watch the eyes and breathing every morning. If coughing, sneezing or swollen faces appear in more than a few birds, call your vet.
Should I keep the house fully closed during the harmattan?
No. A fully closed house traps ammonia and moisture overnight, and birds breathing that air at dawn are at more risk than they are from the cold. Shut the curtains on the windward side, keep the high vents open a little, and stop cold draught reaching the birds at their level. A little steady air movement is the goal.
How do I keep young birds warm on cold harmattan nights?
Use a heat source you can adjust, and check it at night with a torch. Watch the birds rather than the thermometer. Spread birds mean the heat is about right. Birds piling in one corner mean too cold or a draught. Our brooder guides cover heat sources and piling in more detail, so read those before the first chicks arrive.
Why are my birds drinking so much in the dry season?
Dry air pulls moisture from the birds, and they replace it by drinking. Intake also rises when birds are warm, and they crowd near the drinkers in the afternoon when the air is still. Check that the drinkers flow at the far end, that they sit at the right height, and that the water is clean. If intake jumps and the birds look unwell, call the vet.
Should I change the feed for the harmattan?
Do not change the feed on your own because of the weather alone. Cold nights can raise the birds' energy needs, and your nutritionist can advise whether an adjustment makes sense for your flock and feed. Keep the feed covered and fresh, fill feeders in smaller rounds, and watch the daily intake. That number will tell you more than any change of bag.
When should I call the vet during the harmattan?
Call the vet the same day if several birds have watery eyes, swollen faces, noisy breathing or a sudden drop in eating and drinking. Do not wait a week to see whether it passes. Respiratory signs can spread quickly through a flock, and the earlier the vet sees the birds, the more choices you have.
Are chicks at more risk during the harmattan?
Chicks are more sensitive to cold, dust and damp, so the brooder needs closer checking in the harmattan. The biggest risks are chilling, piling and dusty litter. The standard to aim for is a warm, dry, draught-free brooder with clean water and feed set out early. Our chicks are vaccinated at the hatchery and dispatched on the day they hatch, but they still need a stable brooder to start well.
