Layer House Temperature and What Heat Does to Egg Production

Discussion of house temperature almost always centres on broilers. Yet layers face a different problem: the cycle is not 35 days but more than a year, and heat losses show up as gradual production decline rather than sudden visible mortality.

Reference range for layers

For laying hens in production, the comfort zone commonly used as a reference is 18–24 °C, at 50–70% relative humidity.

Outside that range:

Condition	What happens
Below 18 °C	Feed intake rises to generate body heat; FCR worsens
18–24 °C	Optimal zone — best production and feed efficiency
25–29 °C	Feed intake starts falling; production holds but egg weight shrinks
30–32 °C	Production drops clearly; shell quality declines
Above 32 °C	Sharp decline; mortality risk under prolonged exposure

These are general reference figures. The layer strain guide you run publishes its own official table — use that as the primary reference.

The reality to face: in the Indonesian lowlands, 18–24 °C is essentially unreachable during daylight without cooling. The realistic target is holding temperature as close as possible to the top of the comfort zone through the hottest hours.

How heat cuts production

The chain is sequential and observable.

Feed intake falls. Digestion generates metabolic heat. A bird already overheating avoids it instinctively. Since eggs are built from feed nutrients, reduced intake feeds straight through to production.

Egg weight shrinks. This is usually the first measurable effect, appearing before egg numbers fall. Hens still lay daily, but the eggs are smaller — a grade shift that shows up directly in price.

Shell quality declines. Panting expels excess CO₂ from the blood. That shifts acid-base balance and disrupts calcium availability for shell formation. Shells thin, crack more readily, and breakage rates rise.

Egg numbers fall. If heat pressure persists, daily production follows.

Recovery is not immediate. After a heat wave passes, production takes time to return. A few days of extreme heat can affect performance for weeks.

That last point is what makes heat more expensive in layers than it appears: the loss has a long tail.

Why layers are more exposed than expected

Continuous exposure. Broilers go through a few critical weeks and then to harvest. Layers face every hot season across their entire production life.

Density and stacked-cage heat. Tiered battery systems put many birds in a relatively small air volume. Heat accumulates, and upper tiers usually run hotter because warm air rises.

Hidden losses. Mortality is visible and counted immediately. A two-gram drop in egg weight and a rise in cracked eggs are often not tracked with the same discipline, yet their effect is cumulative and large.

Humidity matters just as much

As with broilers, humidity determines whether panting can still cool. In high humidity, evaporation from the respiratory tract slows and the bird’s primary cooling mechanism loses effectiveness.

At 30 °C and 60% RH a layer can still compensate. At 30 °C and 85% RH that capacity is much reduced. Same thermometer reading, very different bird.

Which is why measuring humidity in a layer house is not optional — it is part of the data that drives the decision.

Holding temperature in a layer house

The order is the same as for broilers, for the same reasons:

Cut heat coming in. Roof insulation and reflective roof surfaces. In tiered housing, roof radiation onto the top tier is a real load.

Remove the heat present. Ventilation at adequate and even air speed. In battery housing, make sure airflow reaches every tier — not just the central aisle.

Lower the air temperature. Evaporative cooling is the only practical route. Cooling pads condition incoming air; high-pressure misting adds cooling along the house, including zones the pad effect does not reach.

A note specific to layers: because the production period is long, cooling running costs accumulate over years. The power draw difference between a high-pressure system (small pump) and other approaches becomes a material factor on an annual basis.

Sensor-based control. Evaporative cooling raises humidity. In a dense layer house that is already humid, the system must stop before humidity reaches the point where it blocks heat loss.

Daily management that helps

Several steps need no equipment:

• Shift feeding to early morning and late afternoon, away from peak heat
• Ensure cool, abundant drinking water — intake spikes in heat
• Avoid bird handling during the critical hours
• Track egg weight and crack rate, not just egg count — both are early indicators of heat stress

In short

The layer comfort zone (18–24 °C) is not naturally reached in the Indonesian lowlands during daylight. What can be done is holding temperature as close to its upper edge as possible through the critical hours.

Heat losses in layers are gradual and long-tailed: egg weight first, then shell quality, then egg numbers — and recovery lags after the heat passes. Which makes prevention worth considerably more than emergency response.

See our poultry house cooling systems. For a calculation for your layer house, send dimensions, housing type, tier count and flock size over WhatsApp.