What are the problems we often encounter in a poultry hatchery?

- Low hatching rate.
- Low rate of eggs with embryos.
- Many embryos dead at an early incubation stage.
- High rate of rotten eggs during incubation.
- Piped eggs, without hatching.
- Late hatching or chicks not hatching at the same time.
- Complete hatch failure
- Poor quality of day-old birds:
1) Chicks hatch with crippled and malformed legs.
2) Chicks hatch with rough or unhealed navel, wet and dirty feathers.
3)High mortality during the frst week of life

What are the reasons for a low rate of embryos in eggs?

- The male-female rate of the parent flock is not suitable: insufficient or excessive number of roosters.
- Imbalance of maturity or size between males and females also affects mating success.
- Spurs are not trimmed causes severe scratching of hens and then hens will run from mating attempts or roosters have malformed toes making it difficult for them to keep balance on the back of the hens during mating.
- Improper design of the breeding house, affecting the roosters and drakes.

What are the reasons for dead embryos at an early incubation stage?

Dead embryos at early stage can be caused by:
- A diseased parent flock.
- Improper nutrition of breeders e.g. the use of mouldy feed or feed lacking micronutrients
- Eggs are cracked, dirty or wet.
- Improper egg cleaning and fumigation.
- Eggs stored improperly or for too long before incubation.
- Improper incubation parameters such as too high or too low temperature or humidity or insufcient egg turning during the incubation period.
Inbreeding can cause early embryonic mortality

What are the reasons for rotten, exploded eggs during incubation?

- High air humidity during egg storage.
Storage duration * Temperature (oC) * Humidity (%)
7 days**************** 15-18 ***************75-80
4 days ****************18-24 ***************75-80
- Contamination during storage. Activities like sweeping or spraying water on the floor of the egg storage area can deposit large amounts of bacteria on the eggs.
- Failure to clean incubators following an egg explosion leaves bacteria in the chamber that can contaminate other eg

What are the reasons for a high rate of piped eggs that do not hatch?

- Eggs have been stored for too long or at too low or too high a temperature before incubation
- Improper setting of eggs in incubation trays with the small end up.)Pipped eggs might not hatch due to setting the smaller end of the eggs up(
- Wrong turning angle of the egg in the incubator(Proper turning angle of eggs in the incubator is 90o)
- Improper incubation parameters: too high or too low temperature or humidity or insufficient egg turning during the incubation period

What are the reasons for a prolonged hatching time?

Prolonged hatching time is caused by the following reasons:
- Eggs have been stored for different duration.
- Eggs have been stored for too long before setting (see details on proper egg storage duration in the question No 17).
- Different egg sizes and/or breeder ages.
- Embryos have already started developing during egg storage prior to setting.
- Low temperature at the initial stage of incubation (lower than 37.2oC).
- Uneven egg temperature at time of setting – some eggs warm other

What are the reasons for complete hatch failure?

Causes could be power failure, low or high temperature, eggs stored incorrectly, old eggs and equipment failure (fans, ventilation, etc.)

What are the reasons for crippled and malformed chicks and rough or unhealed navels upon hatching?

Te main reasons for crippled and malformed legs, and a rough or unhealed navel upon hatching are as follows:
Improper incubation temperature, usually too high (higher than 38oC) during the second phase of incubation period and the hatching time.
Te eggs are placed with the small end up.
Improper nutrition of breeders: feed lacks micronutrients and/or is mouldy or aflatoxin-contaminated.
Te parent flock has been improperly treated with veterinary drugs
a) Wrong medication, or
b) Higher

What are the reasons for dirty chicks upon hatching?

Main reasons for dirty chicks upon hatching are:
- The humidity in the incubators and hatchers was too high that adversely affected the embryo development leading to those eggs piped but died without hatching and produced a fluid making other chicks dirty (see an illustration picture below).
- Rotten eggs are not removed when they explode in the hatching trays and other eggs and chicks get dirty.
- Rough handling during transfer of eggs from incubator to hatcher – broken, cracked and leaking

Reasons for high chick mortality during the first week

In the frst week, a high mortality rate of chicks is mainly due to:
- Te temperature is too low (below 20oC) in the brooding house and they more easly get infections.
- Drafy/cold areas in the brooding pen.
- Brooding pen too large – chicks get away from heat and are not able to get back.
- Diseases are transmitted vertically from hens to chicks (Salmonellosis, Mycoplasmosis).
- Hatching of the whole batch of eggs takes too long. Tose chicks that hatch early get dehydrated and become w

What is a standard egg for hatching?

A hatchery standard egg is:
- An egg that comes from a parent flock that is bred properly according to good production practices including a proper male/female ratio according to the technical requirements of each species or breed including proper body weight and fed with a nutritionally appropriate feed – good quality.
- Proper weight, not too big, not too small (note that the weight depends on species and breed as some examples in the table below).
No **Poultry breed** Egg weight (g)
1

It is said that an overweight parent flock will lead to a low hatching rate. Is that true?

Yes!
Mating success of overweight males is much lower. Reproductive “season” of overweight males is much shorter.
Overweight females also have erratic laying patterns, affecting quality of the eggs.

How does one ensure collection of clean eggs?

In order to collect more clean eggs, it is necessary to:
- Keep the breeder house clean.
- Keep litter in the house dry and clean – remove and replace areas that get wet.
- Maintain sufcient laying nests in appropriate locations (quiet places; avoiding direct sunshine, easy-to-fnd locations).
- Train hens to lay eggs in nests, minimizing egg lay on the floor.
- Te litter and bedding for the nests must be kept dry and clean.
- Nest should be keep clean from feces and dirt. Regularly co

Why should we avoid setting dirty eggs for incubation?

Dirty eggs can get soiled with feces when hens have diarrhea, or from feces and dirt in wet litter or nests. Ectoparasite infestations also can cause dirty eggs.
These eggs should not be incubated because:
- Transmission of pathogens to clean eggs can occur in incubators.
- Dirty eggs may rot or explode, thus contaminating the incubator and affecting the hatching quality of the whole batch of eggs.
- Dirty eggs normally have a very low hatching rate.
- Bacteria on contaminated eggs can

Why should the bigger end of the eggs be up when placed in incubation trays?

- Embryo will have the proper orientation within the shell.
- The air cell of the egg is at the bigger end of the eggs and having this end up facilitates the respiratory process of the embryos.
- Upon hatching, piping will be easier as the eggshell at the bigger end is thinner than at the smaller end.
- Eggs will crack less often during the turning process of incubation if the bigger end of the egg is up

Why should we exclude eggs with big air cells, slanting air cells and detached, mobile air cells for incubation

When selecting eggs for incubation through candling, eggs with big air cells, slanting air cells and mobile air cells should be excluded because:
- Eggs with big air cells have been stored for a long time or under improper conditions (humidity is too low) and have poor hatching success.
- If the air cells are too slanted, the embryos can develop at the wrong location in the egg leading to low hatchability.
- Detached, mobile air cells mean that the outer and inner egg membrane has been separated and leads to low/no hatchability. Tis is ofen caused by transport on rough roads or rough handling during movement on and off transportation vehicles or if eggs are stored with the small end up.

How to recognize eggs that have been stored for too long?

Eggs stored for a long time (more than 7 days) often have the following characteristics:
- The eggshells are glossy.
- Big air cells are seen upon candling.
- The yolks move quickly upon egg rotation.
- The yolk can sticks to one end of the egg, which can be seen upon candling.