Maximise Your Broiler and Layer Profits This 2026 Winter

Production Management  ·  April 2026  ·  Poultry Technical Series

Winter in Zimbabwe is not the brutal season it is in temperate climates, but it is cold enough — particularly at night and in the early morning — to quietly destroy your profitability before you have realised it is happening. Feed conversion ratio climbs. Egg production drops. Broiler growth slows. Every degree below the bird’s thermal comfort zone is money leaving your operation. This article explains the science behind cold stress in poultry, and gives you a practical management framework for both electrified and non-electrified setups.

Ask most small to medium poultry farmers what their biggest winter challenge is and most will say disease, or feed prices, or electricity costs. Rarely does anyone say temperature management — yet temperature is the single variable that sits underneath all of those problems. A cold bird is a stressed bird. A stressed bird eats more feed to produce less meat or fewer eggs. A stressed bird has a suppressed immune system and is more vulnerable to respiratory disease. Get the temperature right and the rest of your winter management becomes considerably easier.

This is not complicated in principle. It becomes complicated in practice because most small and medium poultry operations in Zimbabwe were not built with winter temperature management as a priority. Ventilation gaps that are essential in October become wind tunnels in June. Concrete floors that drain well in summer conduct heat away from birds in winter. And the energy required to maintain thermal comfort — whether that is firewood, charcoal, or electricity — adds a cost that many farmers try to minimise rather than optimise. That is the wrong approach. The cost of the heat you provide is almost always less than the cost of the feed your cold birds waste and the production they fail to deliver.

Understanding the Science: What Temperature Does to Feed Conversion Ratio

Feed conversion ratio — FCR — is the single most important production metric in a broiler or layer operation. It measures how many kilograms of feed your birds consume for every kilogram of live weight gained (broilers) or per dozen eggs produced (layers). A broiler FCR of 1.6 means 1.6kg of feed for every 1kg of weight gain. The lower the FCR, the more profitable your operation. The difference between an FCR of 1.7 and 2.1 on a 500-bird flock is enormous — it is the difference between a profitable batch and one that barely breaks even.

Temperature drives FCR directly through a mechanism called thermoregulation. Birds are warm-blooded. They maintain a core body temperature of approximately 41°C regardless of the environmental temperature around them. When the house temperature falls below the bird’s thermal comfort zone — called the thermoneutral zone — the bird has two choices: increase feed intake to generate metabolic heat, or sacrifice growth and production. Usually it does both. It eats more. It grows less. It produces fewer eggs. All three of those outcomes are expensive.

The Thermoneutral Zone — What It Is and Why It Changes With Age

The thermoneutral zone is the temperature range within which a bird can maintain its body temperature without expending extra energy on either heating or cooling itself. Within this zone, maximum feed energy goes to growth and production. Outside it — too cold or too hot — energy is diverted to temperature regulation and away from what you are trying to produce.

For broilers, the thermoneutral zone changes significantly as the bird ages:

Bird Age	Target House Temperature	Acceptable Range	Notes
Day 1–3	32–34°C	30–35°C	Chicks cannot thermoregulate. This is the most critical window.
Day 4–7	30–32°C	29–33°C	Still highly vulnerable. Do not reduce heat too fast.
Week 2	27–29°C	26–30°C	Reduce by approximately 2–3°C per week from here.
Week 3	24–26°C	23–27°C	Cold stress risk increases if house is uninsulated.
Week 4	21–23°C	20–24°C	Winter nights in Zimbabwe commonly fall below this.
Week 5–6	18–21°C	18–22°C	Adult broiler range. Still needs active management in winter.

For layers, the optimal production temperature is 18–24°C. Below 15°C, egg production begins to decline noticeably. Below 10°C — which Zimbabwe’s highveld can reach in June and July pre-dawn — egg production can fall by 10 to 25 percent and shell quality deteriorates significantly. Feed consumption per egg produced rises sharply because the bird is burning energy staying warm rather than making eggs.

The FCR Penalty of Cold — Quantifying the Cost

Research across multiple poultry production environments consistently shows that broilers maintained 5°C below their thermoneutral zone for a sustained period show FCR penalties of 0.15 to 0.25 points. A 10°C sustained temperature deficit can increase FCR by 0.3 to 0.5 points. In practical Zimbabwe terms, consider a typical June night in Harare or Marondera where house temperatures without heating drop to 8–12°C. A week-four broiler needs 21–23°C. The deficit is 10–15°C. Without heating intervention, that bird’s FCR will climb significantly above target, and its growth rate will slow correspondingly.

For layers, a flock of 500 birds producing at 85 percent in optimal conditions might drop to 68–72 percent production rate during a cold snap — a loss of 65 to 85 eggs per day. At prevailing egg prices, sustained cold stress over a two-month winter period can cost a 500-bird layer operation several hundred US dollars in lost production, not counting the increased feed cost of birds burning energy on warmth rather than eggs.

Temperature Deficit Below Thermoneutral Zone	Estimated FCR Penalty (Broilers)	Estimated Production Loss (Layers)
1–3°C below optimal	+0.05 to +0.10	2–5% production reduction
4–6°C below optimal	+0.10 to +0.20	5–12% production reduction
7–10°C below optimal	+0.20 to +0.35	12–20% production reduction
More than 10°C below optimal	+0.35 to +0.50+	20–30%+ production reduction, shell quality deterioration

These figures assume sustained cold stress rather than brief overnight dips. The damage is cumulative. A flock exposed to cold nights for three to four weeks does not just have lower production on cold nights — it carries a production and FCR deficit for the rest of the cycle because the birds have been chronically stressed.

Cold Stress, Immunity, and the Disease Connection

Temperature stress suppresses the immune response in poultry. A bird spending significant metabolic energy on thermoregulation has less capacity to mount an effective immune response against pathogens. This is why respiratory disease — Newcastle, Infectious Bronchitis, Mycoplasma — clusters in the winter months. The pathogens are always present; the birds are simply less able to resist them when cold. Good temperature management is therefore not just a production intervention — it is a disease prevention strategy. The cost of a respiratory outbreak in a winter flock almost always exceeds the cost of the fuel you would have used to keep the house warm.

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Step One Before Everything Else: Measure What You Are Managing

You cannot manage house temperature without measuring it. This sounds obvious but is consistently the most under-invested area in small and medium poultry operations. A farmer who walks into the house in the morning and says “it feels cold” is making production decisions on guesswork. By the time it feels cold to a human entering from outside, the birds have typically been cold for several hours.

The minimum equipment requirement for any serious winter management programme is a thermometer placed at bird level — not at human head height, not near a heater, not on the wall in a corner. At bird level, in the middle zone of the house, away from direct heat sources and away from ventilation openings. This is the temperature that matters. The temperature at the ceiling or near the heater is irrelevant to the bird.

For operations with more than 200 birds, a min-max thermometer is strongly recommended. This records the minimum and maximum temperature reached over a 24-hour period, allowing you to see what is happening overnight when you are not in the house. A min-max thermometer costs a fraction of what one day of poor FCR costs on a 500-bird flock, and the information it provides is invaluable for calibrating your heating programme.

For larger operations — 1,000 birds upward — digital temperature data loggers or wireless temperature monitors that log readings continuously and can be reviewed on a phone or computer are increasingly affordable and represent a genuine return on investment. Knowing that your house dropped to 9°C at 3am on Tuesday, when you expected it to stay at 18°C, allows you to diagnose and fix the problem rather than discovering the FCR damage at the end of the batch.

Temperature monitoring equipment is not optional for profitable winter production. It is the foundation on which everything else is built.

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Structural Management: Insulation and House Preparation

Before you spend money on heat generation — whether firewood, charcoal, or electric heaters — you need to reduce the amount of heat you need to generate. Heat retention is always cheaper than heat production. A well-prepared house in winter requires significantly less heating input to maintain the same temperature as a poorly prepared one.

Sealing Ventilation Gaps

The ventilation openings that protected your birds from heat stress in November are now the primary source of heat loss in June. Side curtains, ventilation panels, and open eaves that were held open in summer should be managed carefully in winter — closed at night and in the early morning, opened partially during the warmest part of the day to control ammonia and moisture buildup, then closed again before sunset. Draught — a direct cold airflow across birds at their level — is particularly damaging and should be eliminated entirely. Block gaps at the base of walls with sacking or boards. Check that your curtains reach the ground when closed.

Litter Management

Litter in good condition generates significant microbial heat. Deep, dry, well-managed litter is one of the most effective and cheapest sources of supplemental warmth available to a poultry farmer. Turn litter regularly to prevent caking. Remove wet patches immediately — wet litter does not generate heat and creates ammonia, which further stresses the respiratory system of birds already cold-stressed. Litter depth should be maintained at 8–12cm through the winter cycle.

Stocking Density Adjustment

Bird bodies generate heat. In winter, a modest increase in stocking density — within welfare limits — helps maintain house temperature through collective body heat. This is not a substitute for active heating but it reduces the heating load. For broilers, winter stocking at the upper end of your normal density range (not exceeding welfare guidelines) is a legitimate management tool. For layers in cages, ensure birds are not draughted even if cage placement means some birds are closer to wall openings.

Ceiling and Roof Insulation

Heat rises. An uninsulated metal roof loses the majority of house heat within hours of the heater being turned off. Even basic ceiling insulation — hessian sacking, cardboard, or proper insulation boards — dramatically reduces heat loss and cuts fuel consumption. For operations investing in long-term infrastructure, reflective insulation panels fitted to the underside of the roof make a measurable difference to both winter heating costs and summer heat stress. The payback period is short when calculated against fuel savings.

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Heat Generation: Non-Electrified Setups (Firewood and Charcoal)

The majority of small poultry operations in Zimbabwe’s rural and peri-urban areas operate without reliable grid electricity. For these operations, winter heating relies on biomass — principally firewood and charcoal — used in a range of improvised and purpose-built heating devices. Done well, biomass heating can maintain adequate house temperatures. Done poorly, it is dangerous to birds, dangerous to people, and wasteful of fuel.

The Fundamental Rule: Never Burn Open Flame Inside a Closed House

Open fires — an exposed wood fire burning on the floor or in a brazier with no flue — are the most dangerous heating method available. They consume oxygen. They produce carbon monoxide. In a closed house, carbon monoxide builds to lethal concentrations faster than you might expect, particularly in small houses with good insulation. It kills birds silently overnight. Open fires also produce particulates that damage the respiratory mucosa of birds, making them more susceptible to bacterial and viral respiratory infections. If you are using any combustion-based heating system, the combustion gases must be vented outside the house. The heat stays in. The gases go out.

Firewood — Closed Stoves with Flues

The correct approach to firewood heating is a closed metal stove — commonly called a rocket stove or a drum stove — connected to a flue pipe that exits through the wall or roof of the house. The stove burns wood inside a sealed or near-sealed combustion chamber. The heat radiates from the hot metal body of the stove into the house. The combustion gases — including carbon monoxide and particulates — exit through the flue to the outside. This is a safe, effective system when built correctly.

Practical guidance for firewood stove heating in broiler and layer houses:

Stove placement. Place the stove toward the centre or the cold end of the house — not against an outside wall where the heat is lost immediately. In a rectangular house, one stove of adequate capacity placed in the middle third of the house, with a flue running along the ceiling line before exiting, provides the most even heat distribution.

Flue design. A longer flue pipe running inside the house before exiting extracts more heat from the combustion gases before they leave the building. Even two to three metres of horizontal flue pipe inside the house adds meaningfully to heat output per kilogram of wood burned.

Fuel. Hardwood burns hotter and longer than softwood. Mopane, acacia, and msasa are excellent firewood for poultry house heating in Zimbabwe. Dry, seasoned wood burns significantly more efficiently than green or wet wood — a critical point given that wet wood also produces more smoke. Stack your firewood under cover and allow it to season for at least three months before use if possible.

Loading schedule. The most dangerous period for temperature drop in an unelectrified house is the pre-dawn hours — typically 2am to 6am — when the last night’s fire has burned down and the next day’s warming has not yet begun. Load the stove with a large charge of hardwood at 9–10pm that will burn through until 2–3am. Have someone check and reload at that point if the flock is young or the weather is severe. For older broilers and adult layers in mild weather, a single large loading at nightfall may be adequate — check your min-max thermometer each morning to verify.

Wood consumption estimation. A well-managed closed stove in a 100-bird broiler house will typically consume 15–25kg of dry hardwood per cold night in Zimbabwe’s highveld winter. A 500-bird house will require proportionally more. Budget for this in your cost of production calculation before the batch starts, not after the fuel bill arrives.

Charcoal — Braziers with Forced Fluing

Charcoal is a higher-energy fuel than firewood — it burns hotter for longer per kilogram. It is also more expensive per kilogram. In unelectrified setups, charcoal braziers are commonly used because they are simpler than stove-and-flue systems. However, a standard open brazier is dangerous for exactly the same reasons as an open wood fire — carbon monoxide production in a closed house is lethal. If you use charcoal, the brazier must be connected to a flue that exits the house, or alternatively it must be used in a semi-open house where sufficient fresh air exchange prevents dangerous gas accumulation.

A compromise approach used successfully by many farmers is the use of a metal drum brazier with a tight-fitting lid and a short flue pipe through the wall. The charcoal burns in the drum, the flue removes gases, and the drum radiates heat. The lid allows you to control the burn rate by restricting airflow, extending the burn time per loading.

Charcoal quantity guidance. A 20kg bag of good charcoal will heat a 100-bird house through a cold night when used in a flued drum system. For larger houses, scale accordingly. Charcoal is most economical when used to supplement rather than replace a primary wood heat source — use wood as the main fuel through the early evening when someone is present to tend the fire, and switch to a large charcoal loading at bedtime for the overnight burn.

Chimney Brooder Systems for Chick Heating

For brooder management of day-old to three-week chicks in non-electrified settings, the chimney brooder — a metal cone or box suspended above the chick area with a flue pipe above it — is an effective and widely used system in Zimbabwe. The brooder radiates downward heat from a charcoal or wood fire burning above the flock level, with gases exiting through the flue above. The key variable is height — raising or lowering the brooder body adjusts the temperature at chick level. Use your thermometer at chick level, not at the brooder, to set height.

Chick behaviour is your best real-time thermometer even without instruments. Chicks that huddle tightly under the brooder are cold. Chicks that spread evenly under and around the brooder are comfortable. Chicks that move away from the brooder entirely are too hot. Train yourself and your workers to read this behaviour every time they enter the house.

Additional Strategies for Non-Electrified Houses

Double-wall curtaining. Hang a second layer of curtain or sacking 30–50cm inside the first layer. The air gap between the two layers acts as insulation. Simple and effective.

Temporary ceiling lowering. In winter, drop a hessian or plastic ceiling below the actual roof line using wire or rope. The reduced air volume above the birds is much easier and cheaper to heat than the full house height. Remove or raise it when warm weather returns.

Windbreaks. If your house is exposed to prevailing cold winds from the south or south-east — the dominant winter wind direction in Zimbabwe — erect a windbreak on that face. Grass, hessian, or corrugated iron can reduce the wind chill effect on the building significantly and reduce the volume of cold air infiltrating through gaps in the fabric.

Hot water bottles and thermal mass. For very small operations or emergency cold snaps, dark-painted water containers filled with hot water during the day retain heat through the night. A 200-litre drum painted black, filled with hot water during daylight hours, can release meaningful heat overnight through radiation. This is a supplement, not a primary heating strategy, but it has zero fuel cost beyond what you use to heat the water.

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Heat Generation: Electrified Setups

Operations with reliable grid electricity or generator backup have access to significantly more controllable heating systems. Controllability is the key word — an electric heating system that maintains consistent temperature automatically, without someone managing a fire overnight, is worth paying for in improved FCR and reduced labour stress.

Electric Brooders and Radiant Heaters

For chick brooding, electric radiant brooders — a heating element suspended above the chick area with a reflector dish — are the most widely used system in electrified operations. They are simple, reliable, and easy to height-adjust to control temperature. The same chick behaviour cues apply — spread evenly equals comfort, huddling equals too cold, avoiding the brooder entirely equals too hot. Electric brooders should be on a reliable circuit with adequate amperage for the flock size and should be tested before the chicks arrive, not after.

Thermostatic Control — The Single Biggest Upgrade Available

Whether you are using electric brooders, heat lamps, fan heaters, or a gas-electric hybrid system, adding a thermostat to your heating system is transformative. A thermostat turns the heater off when the house reaches the target temperature and back on when it drops below. Without a thermostat, a heater runs continuously — often overheating the house and wasting electricity — or is manually switched on and off, which means someone must be present to manage it overnight. With a thermostat, your heating system maintains a consistent temperature automatically, the birds are never over- or under-heated, and your electricity consumption is minimised to what is actually needed.

Digital thermostatic controllers suitable for poultry house use are available from agricultural suppliers and cost a fraction of one batch’s electricity bill. They typically have a sensor probe that sits at bird level and a display showing current temperature and target temperature. They are worth fitting to every electrified heating circuit in a poultry house.

Heat Lamps

Infrared heat lamps — either incandescent or ceramic infrared emitters — provide localised radiant heat. They are appropriate for supplemental brooding or for heating specific areas of a house. Their limitation is that they heat the area directly below them rather than the house air temperature uniformly, so in a large house several lamps are needed for even heat distribution. They are a cost-effective option for small to medium operations and are simple to install and replace. Ceramic infrared emitters last significantly longer than incandescent bulbs and produce comparable heat output.

Gas Heaters (LPG)

LPG radiant heaters — burning bottled gas — are used in larger commercial operations and represent an intermediate option between biomass and full electric heating. They produce clean combustion, minimal particulates, and can be fitted with thermostatic controls. However, as with any combustion system, they must be properly flued or used with adequate ventilation. The carbon dioxide produced by gas combustion accumulates in a sealed house and causes respiratory stress in birds even in the absence of toxic carbon monoxide levels. LPG heating is most effective in houses with controlled minimum ventilation rather than fully sealed ones.

Fan Heaters and Forced Air Systems

Electric fan heaters distribute warm air actively through the house and are effective at maintaining uniform temperature across larger spaces. They are most economical on thermostat control. Their limitation in winter is that the moving air they create can exacerbate wind chill if they are poorly positioned — do not direct a fan heater directly at chicks or birds. Use them to circulate heat within the house rather than to blow it at the flock.

Combined Ventilation and Heating Management in Electrified Houses

The challenge in any well-sealed winter house is balancing heat retention against air quality. Birds produce moisture through respiration and excreta. Ammonia builds from litter. Carbon dioxide builds from respiration. A house sealed tightly enough to retain heat will accumulate these gases to harmful levels within hours. The solution is minimum ventilation — controlled, small volumes of fresh air exchange that are enough to manage air quality but not enough to cause significant heat loss or draught. In an electrified house, this is managed through timed or thermostatically controlled small ventilation fans running briefly and intermittently. The rule of thumb is that you should not be able to smell ammonia strongly when you enter the house. If you can, ventilation is insufficient regardless of temperature.

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Monitoring, Recording, and Adjusting — The Management Loop

Temperature management without record keeping is guesswork. The following minimum records should be kept through the winter cycle:

Daily temperature log. Record the minimum temperature reached overnight (from your min-max thermometer or data logger) and the temperature at mid-morning after the house has begun to warm. Do this every day. A simple handwritten log on the wall of the house is adequate. After two weeks you will have a pattern that tells you exactly what your house does in different weather conditions and whether your heating programme is adequate.

Weekly FCR calculation. Weigh a representative sample of birds weekly. Record total feed consumed. Calculate FCR for the week. If FCR is climbing without a clear age-related explanation, review your temperature log for the same period. Cold nights will show in FCR data within three to five days.

Egg production daily record (layers). Count and record eggs every day. A sudden or sustained drop in production rate — particularly if accompanied by increased feed consumption — is a strong indicator of cold stress in the absence of other disease signs. Cross-reference with your temperature log.

The value of these records accumulates over time. After two winters of consistent record keeping, you will know exactly what your house does in cold weather, what fuel or electricity your heating programme requires, and what the FCR and production impact of different management approaches has been. That knowledge is worth more than any single production intervention.

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Quick Reference Summary

Strategy	Non-Electrified Setup	Electrified Setup	Priority
Temperature monitoring	Min-max thermometer at bird level	Digital thermostat controller with probe + data logger	Essential — do this first
Heat source — chicks	Chimney brooder (charcoal or wood, flued)	Electric radiant brooder on thermostat	Critical in weeks 1–3
Heat source — growers and adults	Closed stove with flue (hardwood) or flued drum brazier (charcoal)	Infrared heat lamps, fan heater, or LPG on thermostat	High — especially overnight
Carbon monoxide risk	Always use flued systems. Never open fire in a closed house.	Ensure LPG systems have adequate ventilation	Non-negotiable safety requirement
House sealing	Close curtains at sunset. Double-layer if possible. Block floor draughts.	Close curtains at sunset. Use minimum ventilation fans for air quality.	High — reduces fuel cost significantly
Litter management	Turn daily. Remove wet patches. Maintain 8–12cm depth.	Turn daily. Remove wet patches. Maintain 8–12cm depth.	High — litter generates heat and affects air quality
Ceiling insulation	Hessian, cardboard, or drop ceiling of plastic sheeting	Reflective insulation panels under roof	Medium-high — long payback for permanent structures
Ventilation management	Minimum daytime ventilation to manage ammonia. Closed at night.	Timed or thermostatically controlled minimum ventilation fans	High — balance heat retention against air quality
Windbreaks	Grass, hessian, or corrugated iron on cold exposure face of house	Same	Medium — particularly for exposed sites
Record keeping	Daily min temperature log. Weekly FCR. Daily egg count.	Daily min temperature log. Weekly FCR. Daily egg count.	Essential — cannot improve what you do not measure

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The Bottom Line: Heat Is an Input, Not an Expense

The mental shift that separates profitable winter poultry producers from unprofitable ones is simple: they treat heating as a production input — like feed or medication — with a measurable return, not as an overhead to be minimised. Every kilogram of firewood or bag of charcoal you burn to keep your house at the right temperature is returning multiple times its cost in improved FCR, sustained production, and healthier birds. Every degree below thermoneutral that your birds spend because you were trying to save fuel is costing you more than the fuel you saved.

Start with your thermometer. Know what your house actually does overnight in June. Build your heating programme around the data, not around guesswork. Monitor your FCR weekly. Adjust. Record. The farmers who do this consistently are the ones whose winter batches are as profitable as their summer batches — and in a market where egg and chicken prices are often higher in winter due to reduced supply from cold-stressed flocks, the opportunity is real.

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Looking for temperature monitoring equipment, heating supplies, or quality broiler and layer feed for your winter cycle? Browse our equipment supplier directory or find feed manufacturers near you.

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Technical temperature and FCR data in this article are based on published poultry science research and industry guidelines from the Poultry Association of Zambia, the South African Poultry Association, and international broiler management manuals. Specific figures are indicative ranges and will vary with breed, house design, altitude, and management. Always cross-reference with your feed supplier’s or breed supplier’s specific management guidelines for your flock.