Chicken Incubation Process

Comprehensive workflow of a chicken hatchery: Standardized operations from hatching eggs to chicks (Draft, content and images to be improved)

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I. Main Incubation Process

The entire incubation process can be summarized in a clear workflow:

Egg Arrival → Disinfection Room → Egg Storage → Pre-warming Room → Incubator → Candling → Transfer → Hatcher

Let’s break it down one by one.

1. Egg Arrival at Disinfection Room

Purpose: Block external pathogens. The surface of hatching eggs is not sterile; direct storage will cause pollutants to multiply rapidly.

Common disinfection methods:

Formaldehyde-Potassium Permanganate Chemical Fumigation: 42 mL formaldehyde + 21 g potassium permanganate per cubic meter, sealed disinfection for 30 minutes. Can kill Salmonella, E. coli, etc., on the eggshell surface.
Paraformaldehyde Heating Fumigation (Solid Formaldehyde Fumigation):
- 7 g paraformaldehyde per cubic meter, placed in a preheated container on an induction cooker.
- Sealed fumigation for 30 minutes.
- Heat the neutralizer ammonium bicarbonate, theoretical ratio 1.58:1, practical operation 12 g per cubic meter.
- Neutralize for 30 minutes, exhaust for 2 hours.

Chicken eggshells are more prone to attaching pollutants, so disinfection must be thorough. After disinfection, ventilate as required to ensure no residue remains.

2. Hatching Eggs Entering Storage

Purpose: Induce embryonic diapause and wait for the optimal incubation time.

Key parameters:

Item	Parameter
Storage Temperature	Around 18℃ (Must be lower than physiological zero 23.9℃)
Relative Humidity	70%～75%
Storage Time	No more than 7 days, optimal 3～5 days
Turning Frequency	Once per hour

Resting phase: If hatching eggs have been transported long distances, resting is recommended to let the yolk settle and the blastoderm face up. If the breeder farm is close and transport vibration is minimal, this step can be omitted.

3. Hatching Eggs Entering Pre-warming Room

Purpose:

Prevent “sweating”: Cold eggs entering a high-temperature environment will condense water droplets on the surface, hindering gas exchange and breeding bacteria.
Prevent heat shock: Allow embryos to gradually adapt to temperature changes, avoiding decreased vitality or death.

Technical parameters:

Pre-warming room temperature: 22℃～25℃
Resting time: 6～12 hours

4. Hatching Eggs Entering Incubator

Incubation period: Chicken eggs usually take about 21 days (varies by breed)

Temperature plan (Taking tunnel incubators as an example):

Early stage (Few eggs, no old eggs): Setpoint 37.9℃, if left and right tunnel temperatures are low, adjust to 37.95℃ or 38℃.
Late stage (Increased egg volume): Setpoint 37.7～37.8℃, ensure left and right tunnel temperatures are around 37.8℃.

Turning management:

Turning cycle: 1 hour
Turning angle: About 45 degrees
Turning air pressure: 0.4～0.6 MPa, pressure reducing valve set to 0.5 MPa

Damper setting: The incubator damper is set to 0 throughout the process; the damper will automatically adjust when the temperature is inappropriate.

5. Candling, Transfer, Entering Hatcher

Candling: Conduct candling on the 18th day, retain live embryos, and remove dead embryos.

Transfer: Moving hatching eggs from the incubator tray to the hatcher basket is called “transfer”.

Hatcher parameters:

Item	Parameter ()
Temperature	Comprehensive consideration based on equipment model, region, etc.
Humidity	Comprehensive consideration based on equipment model, region, etc.
Damper	Comprehensive consideration based on equipment model, region, etc.

Hatching operations:

On the 20th day, chicks begin to pip successively.
When the hatch rate reaches about 70%, start picking chicks with dry down.
Weak chicks can be manually assisted, but modern industry tends to natural elimination.

Disinfection management:

The incubator (clean area) and hatcher (dirty area) are strictly disinfected in separate zones, utensils are dedicated, and cross-mixing is not allowed.
Internal disinfection: Formaldehyde + potassium permanganate fumigation, 42 mL formaldehyde + 21 g potassium permanganate per cubic meter, fumigation and neutralization for 30 minutes each, ventilation for 2 hours.

II. Pre-shipment Process for Chicks

Hatch → Chick Pulling → Sexing → Beak Trimming + Vaccination → Boxing and Shipping

1. Chick Pulling

Time window: Complete picking within 4～8 hours after hatching. At this time, the down is dry, vitality is moderate, and meconium has not been excreted in large amounts.

Picking method: Manual picking from the hatcher basket, the technique is “grab both shoulders” or “hold waist and back”. Strictly forbidden to lift wings, hold one leg, or pinch the neck.

Automated equipment: Modern intelligent machines integrate chick pulling, chick-shell separation, counting, boxing, cleaning, and basket placement. After separation, chicks are counted by infrared and boxed.

Healthy chick standards: Referring to the quality assessment indicators specified in T/CAAA 054-2020, check appearance, mental state, navel healing, activity ability, etc.

Defect elimination: Omphalitis (black navel, button navel), large belly, blind eye, lame leg, deformity, dry purple down, poor yolk absorption.

Placement: Healthy chicks are placed in hollow, breathable chick transport boxes, quantified per box to avoid squeezing.

2. Sexing

Vent sexing: Gently hold the chick with the left hand, gently press the abdomen with the thumb to defecate, use the right hand to part the down around the anus and open the cloaca. The presence of a clear genital papilla indicates a male; absence or extremely small/degenerated indicates a female.

Biosecurity key points:

After finishing each box (about 100 chicks) or every 30 minutes, thoroughly disinfect hands with 75% alcohol.
Keep the sexing table dry, spray disinfectant every 2 hours.
Male and female chicks are placed in different colors or clearly marked transport boxes.

Male chick handling: Conducted in a dedicated waste disposal area, located downwind of the plant, relatively isolated from the production area, in compliance with animal epidemic prevention requirements.

3. Beak Trimming + Vaccination (Beak Trimming and Immune Integrated Machine)

Beak trimming operation:

Within 24 hours of hatching (synchronized with immunization).
Infrared beak trimming or 700±20℃ high-temperature blade, modern industrial hatching commonly uses beak trimming and injection integrated machines to automate beak trimming and vaccine injection.
Cut 1/2 of the upper beak, 1/3 of the lower beak.
The distance from the lower edge of the nostril to the tip of the beak after trimming is about 2 mm.

Vaccination (First immunization after hatching):

Vaccine Type	Inoculation Method	Dose
Marek’s Disease Vaccine	Subcutaneous injection in the neck	0.2 mL/bird
Newcastle Disease + Infectious Bronchitis Combined Vaccine	Spray or eye/nose drop	Follow standards

Injection site: Subcutaneous at the middle-lower 1/3 of the dorsal midline of the neck. Strictly forbidden to inject into the ventral side of the neck or muscle layer.

Place gently after immunization and observe for 10～15 minutes. If neck swelling, fluid leakage, or allergic reactions are found, immediately re-inject or isolate.

4. Boxing and Shipping

Final inspection review: Check each chick for neat beak trimming, only needle holes at the subcutaneous injection site on the neck, eliminate injured chicks, and sample check the accuracy of sexing.

Boxing specifications:

Use dedicated food-grade chick transport boxes (paper or plastic), with ventilation holes around the box and at the bottom.
Chick density:
- Spring/Autumn: 100～104 birds/box
- Summer high temperature or long-distance transport: 80～85 birds/box
- Winter long-distance: No more than 104 birds/box
Labels on the outside of the box indicate breed, sex, quantity, hatching date, immunization items, hatchery information, destination, and quarantine certificate number.

Packaging and transfer:

When loading, boxes are stacked in a staggered manner to avoid blocking ventilation holes and maintain smooth ventilation.
Paper boxes no more than 8～10 layers, plastic boxes no more than 12～15 layers.
Temperature inside the carriage: 24～28℃ (Winter 26～28℃, Summer 24～26℃).
Drive smoothly during transport, speed: First-class road ≤60 km/h, highway ≤80 km/h.
Ensure delivery to the farm within 24 hours after hatching, high-quality standard is 12～18 hours.
Inspection during transport: First time 2 hours after departure, then every 2 hours, final inspection 30～50 km from destination.

III. Troubleshooting

1. Turning Failure Troubleshooting Process

Check if the egg trolley is pushed in place; if it rolls, an alarm will sound.
Check if the air pipe is connected or forgotten to be connected.
Pull out the air pipe connector, turn manually to see if it can turn in place.
If not, it may be that the egg trolley iron frame is deformed and stuck due to transport squeezing; tap and adjust.
Check if the wiring of the turning detection box is incorrect.
If correct, it indicates a problem with the Hall proximity switch; replace the spare part.

2. Main Control Low Temperature Alarm Caused by Main Control Probe Quality Issue

The internal temperature of the cabinet is normal, but the main control low temperature alarm is triggered irregularly. The alarm time is extremely short, automatically eliminated in seconds to tens of seconds. After ruling out water droplets dripping, it is judged that there is a problem with the probe itself; the problem is solved after replacing the probe.

3. Hatcher Temperature, Humidity, and Other Parameters Cannot Be Adjusted

First situation: The hatching plan is not selected. Click to use the selected plan, then adjust the parameters.
Second situation: The hatching time is set to a future time, and the page shows pre-warming or pre-warming delay. Only when the start hatching time is less than the current time can the set temperature be changed.

4. Hatcher Humidity Alarm, Tunnel Incubator Temperature Deviation Issue

Single hatcher humidity too high: Check the wet bulb thermometer, water box, cloth strip, check the nozzle, water pipe, solenoid valve, main control board.
All machines report low temperature: Most likely a water outage, check the pressure tank, water pump, main power supply.
Tunnel incubator temperature deviation: Check the thermometer, probe deviation, check the egg trolley seal (baffle and rolling phenomenon). If there are no problems with the above, one probe on the low-temperature side can be removed.

5. Negative Pressure Exhaust Feather Removal Air Pressure High/Low Alarm Resolution

The negative pressure channel keeps alarming, and the air pressure value is too high or too low. Reason: Condensed water condensation on the sintered copper filter head (recent filter head/silencer joint) at the end of the differential pressure sensor, water contamination during cleaning, and blockage by foreign matter such as feathers. Wipe off the water and foreign matter on the filter head to restore normal operation.

References

GB/T 40454-2021, Good manufacturing practice for poultry hatching [S].
NY/T 1893-2020, Technical code of practice for poultry hatching [S].
NY/T 4255-2022, Technical specification for facility and equipment configuration of large-scale hatcheries [S].
T/CAAA 088-2022, Technical specification for transportation of day-old chicks [S].
T/CAAA 054-2020, Quality assessment of day-old chicks [S].

Conclusion

The full-chain management of a chicken hatchery lies in the precise control of the five core elements: temperature, humidity, ventilation, turning, and disinfection, as well as the strict implementation of biosecurity. Negligence in any link may lead to a decline in hatchability or damage to chick quality.

Note: The above parameters should be flexibly adjusted for incubation duration, temperature, humidity parameters, and operational details according to the actual chicken breed and region. It is recommended to continuously optimize based on on-site operational data.