hatchery management

1. Egg handling and selection 2. Egg disinfection 3. Egg storage 4. Egg quality control

4 key areas of hatchery management

At least 4 times a day; more often in hot climates

How often should eggs be collected on a farm?

To clearly distinguish and reduce contamination risk.

Why should nest eggs be collected separately from floor eggs?

rough handling

can cause cracks/damage the chalazae and internal membranes resulting in higher embryo mortality. Beware of eggs rolling too fast off conveyor belts from automatic nest that can cause cracks.

Between 50 and 68 grams (depending upon flock age)

Ideal weight range for hatching eggs?

egg hatching selection

have clearly defined round and pointed ends, good colour, clean and undamaged shell free from infection. Egg weights and grading will vary by individual operations and need for eggs.

Conditions of the eggs

has been shown to have negative impacts upon performance including:

• dirty eggs

• cracked eggs

• mis-shaped eggs

• double yolks

• upside down eggs

dirty eggs and cracked eggs

reduced hatchability and higher risk of contamination (Omphalitis and Aspergillus)

mis-shaped eggs

reduced hatchability and higher cull levels

double yolks

reject egg, no hatchability.

upside down eggs

reduced hatchability and more culls.

egg storage environment

From the time the egg is laid until storage in the hatchery, the temperature profile should be ‘V’- shaped. The hatchery should have the lowest storage temperature as shown in the flow chart. The environment in the hatchery egg store is normally more controlled than at farm level and deviations from the temperature setpoints are minimal.

• Eggs need to be kept below 24°C after they have been laid

physiological zero

the temperature at which embryo development does not advance

104-106 f

40-41 c

hen’s body

75-85 f

24-29 c

hen’s house

70 - 77 f

21 - 25 c

on farm egg room

68-73 f

20-23 c

egg transportation truck

59 - 66 f

15 - 19 c

hatchery egg room

75 - 80 f

24 - 27 c

preheating area

95.5 - 100 f

37-5 - 37.8 c

incubator machine

1. storage prolongs incubation time. On average, one day’s storage adds one hour to incubation time. This must be taken into account when eggs are set, so fresh and stored eggs should be set at different times.

2. Hatchability is depressed by prolonged storage. The effect increases with storage time after the initial six-day period, resulting in losses of 0.5 to 1.5% per day with the percent increasing as storage extends further.

3. Extended periods of egg storage (8 days or more) result in albumen degradation which may cause the embryo to move close to the eggshell

effect of egg storage

• Reduces the risk of embryo shock.

• Prevents condensation forming on the shell. Condensation can allow bacteria to stick to the shell which increases the risk of contaminating the egg.

• Pre-warming eggs prior to incubation will reduce the variation among egg temperatures at the time of incubating. Similar egg temperatures will narrow the hatch window

benefits of pre-warming eggs

setter operation

Energy consumption, labor usage, durability, maintenance and capital costs influence the design of incubators. The optimum physical conditions for any broiler embryo to grow successfully are:

• Correct temperature

• Correct humidity

• Adequate gas exchange

• Regular turning of eggs

• incorrect ventilation - air volume supply, pressure, damper settings, exhaust ventilation

• temperature calibrations - calibrate the temperature probes of the machine every 90 days for a multi-stage machine and every time a single stage machine is empty

• cooling problems - water flow rates, sticky valves, incorrect water temperature, mineral deposits in the pipes

• over or under utilization of incubator capacities - Machines are calibrated to be full and may not operate within calibrated temperature ranges if not full of eggs

• poor engineering design

• maintenance - door seals are worn, cracked, or broken

• incorrect turning angle - calibrate every 90 days for a multi-stage machine and every time a single stage machine is empty. Adjust if necessary

Factors that can impact uniformity of temperature in the incubator:

• Temperature of incubation: Normally fixed for any hatchery, but to achieve a desired take-off time for chicks, modifications to time can be adapted to age and size of eggs.

• Age of eggs: older eggs take longer to incubate. You will need to add extra incubation time if eggs are stored over 7 days.

• Size of eggs: larger eggs take longer to incubate.

• Moisture loss: Low moisture loss will slow the hatch cycle and decrease hatchability. Excessive moisture loss will decrease the number of incubation hours.

Four factors influence the total incubation time of eggs:

36.6 to 37.7

• too cold

• slow / poor hatch and poor chick quality

37.7 - 38.0

• optimum

• good hatch and good chick quality

38.0 - 38.8

• too warm

• good hatch but poor quality

39.1 - 40.0

• too hot

• poor hatch and poor chick quality

importance of turning

• Turning the egg prevents the embryo from sticking to the shell membranes, particularly during the first week of incubation, and promotes development of the embryonic membranes.

• When the turning angle is too shallow (less than 39°), the incidences of incorrect embryo position increase.

• As embryos develop and their heat production increases, regular turning will redirect airflow throughout the incubator and prevent specific areas from overheating.

• Turning failures that occur during the first week of incubation cause a reduction in hatchability, increase embryonic mortality, and increase the incidence of malposition. Furthermore, the impact of turning failures during the first week cannot be resolved later in incubation.

• Between 3 to 4 days of incubation, the yolk sac membrane is growing down around the yolk and actively moves water from the albumen to the sub-embryonic fluid. Turning allows the yolk membrane to absorb water by contacting a fresh area of albumen.

egg transfer

Eggs are removed from the incubator after 18 or 19 days of incubation and transferred to the hatcher baskets. Transferring too early or too late can result in embryos being subjected to sub-optimal conditions which then can cause lower hatchability and reduce chick quality

• The incubator can be single or multi-stage, but all eggs should be transferred to a single stage hatcher.

• The incubator must remain operating until the last egg is removed from the machine.

• Ensure the hatcher and hatcher baskets are thoroughly washed and allowed to dry before eggs are transferred.

• The hatchers should be turned on at least two hours prior to transfer with the buggies (trollies) and hatcher baskets inside.

• Have all required materials ready and make sure the transfer machine is ready prior to beginning transfer.

• The time between the eggs leaving the incubator and entering the hatcher should be less than 20 minutes to prevent the eggs from cooling.

• At transfer, eggs may be candled by hand to count and remove infertile, early embryonic mortality, and contaminated eggs.

• If manually candling, take a sample of the clear eggs from young, prime and old flocks to check the accuracy of the personnel or equipment.

• Audit transfer crews and check equipment regularly to reduce transfer damage.

• Prior to transfer, all contaminated eggs (“rots” and “exploder”) should be removed and placed in a receptacle with disinfectant.

• Transfer eggs from younger flocks first and transfer eggs from older flocks and floor eggs last.

• In-ovo vaccinations can provide early immunity for the embryo and reduce the need for chick handling, manual labor and personnel errors.

• If hatchers and/or baskets are not dry at transfer, open the hatcher damper fully for the first 3 to 4 hours after transfer to help reduce the humidity

Key points in egg transfer include:

Factors influencing egg size

1.Egg size is the main factor affecting chick size. Chick weight is normally 66-68% of egg eight. Thus, chicks from eggs averaging 60 grams will on average weight around 40 grams. Individual chick weights are likely to range from 34 to 46 grams.

2.Egg weight decreases because of water loss during incubation. This also contributes to chick weight variation from eggs of the same size.

3. Length of time between hatching, pulling, and delivery also affect final chick weight. Time spent in the hatcher will have a greater effect than time at the lower temperature the chick room or delivery vehicle.

1. During processing, chicks must be held in a controlled environment that prevents overheating or overcooling. They must not be overcrowded in the boxes or while on conveyers. To reduce weight loss from the chicks, maintain the correct humidity in the chick holding areas. Aim for 23 °C (73 °F) with a relative humidity of 65 - 70%.

2. Automated equipment has been developed to improve chick handling while reducing the number of staff involved.

3.Avoid rough handling of chicks in manual operations and when equipment is used. Equipment must be correctly and regularly maintained. Clean all equipment thoroughly after each hatch. All chick contact areas such as conveyers and carousel must be easily accessible for cleaning.