Turning chicken eggs: frequency, day-18 stop and tray checks

Turning does not simply “warm the other side”. It regularly changes the egg’s position to help prevent the embryo remaining against the shell membranes and to support normal development. An audible motor does not prove that the eggs are moving.

This guide covers chicken eggs. Timing and methods differ for other species and incubator designs, so the exact manual takes priority.

The principle across four periods

Period	Turning	Main check
Before day 1	Test empty	Tray reaches its real positions without binding
Days 1–7	Regular and recorded	No egg is trapped; daily check completed
Days 8–18	Continue the same method	Linkage, motor and power remain reliable
After day 18	Stop for chicken eggs	Eggs in hatch position; vents and humidity prepared

Mississippi State advises against turning during the final three days before hatch. For a chicken cycle of about 21 days, the transition therefore normally occurs around day 18.

Why turning matters

The FAO explains that regular turning helps prevent the embryo from sticking to the shell membranes. A major absence or irregularity can contribute to embryo loss and poor position at hatch.

Turning does not compensate for:

• incorrect temperature or humidity;
• old or badly stored eggs;
• inadequate ventilation;
• contamination;
• incorrect initial orientation.

It belongs in the complete cycle record rather than being assessed alone.

Manual turning: a simple method

Mississippi State states at least four to six turns per day. The FAO describes five to seven turns and notes that an odd number helps prevent eggs spending every night in the same position.

For a small farm, choose a schedule that is realistic, regular and compatible with the manual. Five well-spaced turns followed every day are more useful than an ambitious plan abandoned after two days.

Mark without damaging

For eggs lying horizontally, use a pencil to place an X on one side and an O on the other. These marks quickly show whether every egg has changed side.

1. Wash and dry your hands.
2. Open the incubator only when ready.
3. Roll each egg gently until the opposite mark is visible.
4. Do not shake, knock or squeeze the shell.
5. Close the machine and record the time.

Do not use a marker or substance whose safety on the shell is unknown. Do not write across a crack or retain a leaking egg.

Egg orientation

Mississippi State says eggs may be set horizontally with the large end slightly elevated, or vertically with the large end up. Never set them small end up.

Use the tray cells as designed. An egg that is too large, too small or badly seated may remain still, touch the lid, trap a neighbouring egg or overload the mechanism.

Test an automatic tray before loading

Incubators use different systems: tilting racks, rocking cradles, rollers or driven cells. Do not infer the expected motion from motor noise alone.

Before adding eggs:

1. install the tray and linkages exactly as the manual shows;
2. run the incubator through several turning cycles;
3. mark the initial tray position and time;
4. confirm that it reaches the expected positions in both directions;
5. observe cables, shafts and moving parts without touching them while energised;
6. simulate loading only by a method or with items permitted by the manufacturer.

Movement may be slow. A few seconds of observation are not enough when the mechanism operates at intervals.

Verify movement during incubation

After loading, use reference positions without opening the incubator unnecessarily.

• Record the visible orientation of two or three reference eggs in different tray areas.
• Check them at spaced times that match the expected cycle.
• Confirm the whole tray changes angle, not only one loose egg.
• Check daily that no egg has left its cell.
• Record every outage, fault and intervention.

When a transparent lid allows observation, use it. Avoid opening only to “see whether the motor turns”.

The motor sounds but the tray does not move

Disconnect and isolate all power before mechanical inspection. Following the manual, look for:

• a disengaged linkage or rod;
• a tray fitted in the wrong direction;
• a trapped cable or poorly seated connector;
• an egg or debris blocking travel;
• excess load or unsuitable egg size;
• damaged gearing;
• a timer not issuing the expected command;
• a power source or voltage that does not match the exact variant.

Never connect a motor directly to mains power or a battery “to test it”. Voltage, polarity, current and control type must be confirmed from the manual or component label.

What if turning has stopped?

First record the last certain position and possible duration of the interruption. Then:

1. protect thermal stability and keep the incubator closed during an outage;
2. restore only the intended power source;
3. check whether the mechanism resumes its normal cycle;
4. if the manual permits manual operation, gently resume the normal schedule;
5. do not perform a rapid series of turns to “catch up”.

An interruption does not guarantee batch failure. Record it and compare later candling and hatch results. For an electrical failure, first follow the power-outage guide.

Move to hatch phase around day 18

Prepare everything before the transition to limit opening:

• confirm the batch’s true age;
• complete the final check in your procedure;
• stop, remove or lock the turning system as directed by the manual;
• place eggs on the recommended hatch surface;
• keep vents unobstructed;
• adjust humidity for the model without wetting electrical parts.

Do not let chicks hatch in a mechanism that is still moving. Never dismantle a tray while it is energised.

Minimum turning record

Day	Mode	Check	Fault / action
Empty test	Automatic	Full travel observed	—
Day 1	Manual or automatic	Time / reference position	—
Days 2–17	Same method	Daily verification	Fault, binding, opening
Day 18	Stop	Tray removed or locked	Transition time

These records become useful when several chicks are malpositioned or hatch rate falls. Use them with the low hatch-rate diagnosis instead of immediately blaming the motor.

A good turning system means real, regular movement, verified before loading and stopped at the right time — not merely an icon blinking on the display.