Incubator First Setup and Calibration: Forced-Air vs Still-Air Temperature

Taking a new incubator out of the box and putting eggs straight in is one of the most common causes of a low hatch. The number on the machine's display is often different from the real temperature at egg level; and forced-air and still-air machines distribute heat in completely different ways. This guide explains how to set up the machine for the first time, how to measure and calibrate temperature correctly, and what to be sure of before you set any eggs.

First Rule: Run It Empty (24-48 Hours)

Before setting eggs, run the machine empty for at least 24, ideally 48 hours. This serves two purposes: letting temperature and humidity settle and stabilize, and letting you get to know the machine and verify its settings. During this time, observe that the temperature stays steady at target, how long it takes to recover after the lid is opened and closed, and the humidity level. Make your adjustments in this empty period, not with eggs inside.

Forced-Air or Still-Air? The Difference That Changes the Temperature

To measure temperature correctly you first need to know your machine's type:

• Forced-air: A fan constantly mixes the air, so everywhere in the machine is at almost the same temperature. The target is 37.5-37.8 °C and you can put the thermometer anywhere inside.
• Still-air: There is no fan; because hot air rises, a distinct temperature gradient forms inside — the top is hotter than the bottom. So in a still-air machine the temperature is measured at the top of the egg, and the target is higher: 38.3-38.9 °C (101-101.5 °F) at the top of the egg.

Not knowing this difference is a classic mistake: someone who sets a still-air machine to 37.5 °C like a forced-air one is actually giving far too low a temperature at egg level, and the hatch is delayed or fails. Positioning the thermometer at the right height is critical in a still-air machine.

Verifying with an Independent Thermometer and Mapping Hotspots

The machine's own display is an indicator panel, not proof; cheap sensors can easily be off by ±1 °C. Before setting eggs:

• Use a calibrated thermometer: Place a reliable, digital thermometer at egg level and compare it with the machine's display. Note the difference; set the machine by this reliable reading, not by the display.
• Look for a hotspot: Measure with the thermometer in different corners of the tray. Especially in still-air machines there can be a difference between the corners and the center; if a zone stays consistently hotter/cooler, plan to rotate the eggs' positions during incubation.
• Thermostat offset: Some machines allow fine-tuning (calibration/offset) on the thermostat; use it to close the gap with your reliable thermometer.

Humidity Setup and Hygrometer Calibration

Like temperature, humidity must be verified. Don't blindly trust the machine's humidity display; compare it with a separate hygrometer. Since cheap hygrometers can be off by ±5-10 points, calibrate yours with the salt test before setting eggs (a saturated salt solution pins humidity at 75% in a sealed container). The step-by-step method and the whole of humidity management are in our incubation humidity guide.

Location, Surface and Level

• A firm, level surface: Set the machine on a stable, level surface; a tilted surface disturbs the humidity and temperature distribution.
• The right room: Choose an indoor space held steadily at 18-24 °C, draft-free and out of direct sun. Room conditions directly affect the machine's interior — details in our seasonal incubation guide.
• Ventilation: Don't block the machine's vents; the embryo needs oxygen.

After Setting the Eggs: The Settling Period

When you set eggs that are at cool room temperature, the interior temperature drops for a while; this is normal. Don't raise the thermostat to close that dip fast — as the eggs warm up, the temperature returns to target on its own, and if you've raised it you'll get overheating instead. Wait a few hours for the temperature to settle. Likewise, humidity drops when the lid opens and recovers in a few minutes; no need to panic.

Checklist Before Setting Eggs

• Has the machine run empty for 24-48 hours and has the temperature settled steady?
• Is the type set correctly (forced-air 37.5-37.8 °C; still-air 38.3-38.9 °C at the top of the egg)?
• Has the temperature been verified at egg level with a calibrated thermometer?
• Has a hotspot check been done?
• Has the hygrometer been calibrated with the salt test and the target humidity reached?
• Is the machine on a level, stable surface and in a suitable room?

The Most Common Mistakes

• Setting eggs directly without running the machine empty.
• Setting a still-air machine to 37.5 °C like a forced-air one (egg level stays far too cold).
• Placing the thermometer at the base instead of the top of the egg in a still-air machine.
• Trusting the machine's display and not verifying with an independent thermometer.
• Trying to "fix" the temperature dip when eggs are set by raising the thermostat (overheating).

Once your machine is calibrated and ready, track your incubation calendar with the KuluçkaTakip app: pick the species, enter the start date, and let it remind you of turning, candling and hatch days. If your hatch turns out low, find the causes in our troubleshooting guide.