Diagnosis of Incubation Problems due to Heredity, False Incubator Settings and Formaldheyde Poisoning.




Findings when candling the eggs


Findings on the embryos during incubation

Day old chicks appearance

Hereditary diseases

Greatly shortened legs, “Mole” foot, wingless, short-beak, Cyclops, encephalocele (cranium bifidum) , eyeless embryos

Aged egg

High mortality at the first days of incubation, lack of embryo growth and development, in terms of the allantois closing and the use of protein.

Irregular shape of the Germinal disc, that displays a foam-like surface

Delayed exodus, many weak day old chicks

 Overheating at the first days of incubation

Part of the batch have well-developed embryos

A lot of deformities of the head, eye and jaw Conclusion of the incubation cycle somewhat earlier.

 Overheating between 3d -5th day of incubation

Most embryos are well developed

Ectopic and deformed heart, stomach and liver

Conclusion of the incubation cycle somewhat earlier.

Short-term acute overheating


Sticking of the embryo to the undamaged shells in the dark blood vessels of the allantois.

Hyperemia and hemorrhage in the skin, liver, kidney, heart and brain, the head is positioned in the yolk

Prolonged overheating during the second half of incubation

Early projection of the beak and the neck of the embryo into the air chamber.

Unused protein at the opening of live embryos, cystic wall of the amnion and the allantois.

Many dead embryos, hatched from the shell but the yolk is not absorbed, irritated yolk sac, intestines, heart, and kidneys, thick intact protein, swelled neck with hemorrhage

Early but elongated hatching small sized and dirty day old chicks, with bleeding umbilical cord.


Under heating at the first half of incubation


Lack of growth and development, in terms of closing of the allantois and the use of protein

Lots of embryos die before hatching, with the following symptoms:

Stunted growth, sticking of the intact protein, to the egg shell. Egg is filled with liquid, mixed with blood; the intestines kidneys and liver are often congested. Neck swelling with hemorrhages.

Output is delayed, the bulk of day old chicks is of substandard quality and weak (defective spinal cord)

Under heating at the second half of incubation

On the 19th day of incubation many embryos are stunted

A lot of the embryos are alive in the egg shell but not hatched. They present the following signs:

Late atrophy of the allantois, swelling of the umbilical ring, rectum full of content from the bile, swelling with hemorrhages in the neck.

Exodus is delayed, a lot of substandard quality day old chicks (enlarged abdomen, swelling of the umbilical ring)

Under heating at the last 2-3 days of incubation

Many dead embryos at hatching with the following signs:

Swelling of the allantois the umbilical ring the neck, enlarged heart. A lot of live embryos pip the egg shell but they are not able to hatch.

Inadequate ventilation

Increased mortality

Hyperemia and hemorrhage of the skin and the internal organs.

Poison gases and vapors of formaldehyde

Great mortality during the first half of incubation, especially at the first 2-3 days

Wrong positioning of the embryo in the middle of the incubation. Congestion of the heart, liver & lungs, bleeding in the allantois, swelling of the neck with hemorrhage

High mortality rate, congestion and edema of the lungs

Excessive  humidity


Delayed closure of the allantois, increased mortality in the middle of the incubation before hatching. Stunting.

Sticking of the beak to the shell while piping.

The crop, the intestines and the stomach are filled with fluid, incorrect positioning of the embryo inside the egg,

swelling, bleeding of the neck,

Atrophy of the allantois.

Belated conclusion of the incubation cycle, big belly



Incubator humidity

Excessive weight loss of the eggs

The embryo is stuck in the middle of the egg. Bleeding of the allantois, undamaged egg shells dry and firm, dry fluff

Day old chicks small, thin and dry

Improper turning of the eggs

Sticking of the yolk to the egg shell, the allantois does not include protein

The protein remains outside the allantois, sometimes drawn into the abdominal cavity with the yolk


Michail J. Mavridis DVM




Incubator VS Broody Hen. Which one is the best?

browordIs the  all natural way ( the broody hen) the best way to obtain chicks?

Is the broody hen solution better than the incubator?

What  are the pros and cons for each solution?

In this article we will try to answer this question and analyze the advantages and disadvantages of each solution separately.

Without doubt, the best incubator is the female bird.

The hen knows her job perfectly  by instinct.

She knows how to turn the eggs in the nest, she knows when an egg is very hot or very cold, when it is barren or dead, and when the eggs hatch, she is the best natural brooding pen.

Here are some of the aspects you should take into consideration before making the final decision which way to use.

Broody Hen Advantages

  • There is no need  for the farmer to collect and store the eggs. The broody hen does this.
  • There is no need  for the farmer to monitor temperature, humidity, and ventilation during the incubation and hatching process.There is also no need to take care for the proper turning of the eggs. Broody hen does this many times a day.
  • The farmer does not  have to worry about power cuts. Broody hen does not use electricity.


Broody Hen Disadvantages

  • Some breeds of poultry won’t  go broody at all. Moreover, especially regarding the “industrial type” hybrids Poultry Genetists have targeted to the genetic selection of individuals on the basis of their reduced tendency for brooding (for at least 100 years now). Many of the backyard poultry from around the globe are descendants of these hybrids.
  • The female bird is usually  broody when you do not need chicks and almost never when you need it.
  • You can’t force a female bird to go broody.
  • Broody hens can only be used seasonally whenever they go broody (usually in the warmer months of the year)
  • The number of eggs a hen can hatch is rather limited and species specific.
  • Broody hens require an isolated and undisturbed area away from the other chickens in order to give a successful hatch.
  • Sometimes the hen abandons the  nest  and the embyos inside the eggs die.
  • Unfertile eggs have a tendency to go unnoticed by the farmer allthough the hen notices them but she can’t take them out of the nest.These eggs may break inside the nest and  scince they are roten spread microbial infection all over the other eggs and can destroy a whole hatch.



Incubator Advantages

  • Incubators are easy to find and cheap to buy these days at least the more basic models that they are widespread.
  • You can go D.I.Y. and make your own incubator if you have basic D.I.Y.skills
  • Can be used any time of the year.
  • We are able to hatch any number of eggs we want and when we want. Capacities of modern incubators range between 12 eggs up to thousands of eggs.
  • It is a wonderful appliance that help us save precious eggs from some rare species of birds.

Incubator Disadvantages

  • The user has to collect and store eggs himself.
  • The user has to monitor temperature and humidity.(or buy automatic)
  • The user has to turn eggs and ensure proper ventilation.(or buy automatic)
  • Some cheap plastic or styrofoam incubators ( of East European and Asiatic origin) have relatively short lifespan and they are equipped with poor quality electronics. Some of  them were proved to be even dangerous to the users. They burn down easily.So  be cautius. Buy from respectable manufacturers. But well constructed incubators  from respectable manufacturers are not cheap.
  • In order to get the best results from the incubator, the user must choose the appropriate place to install it. If the room temperature is high, above 30 ° C  or low, below 15° C you will probably need to operate it inside an air conditioned room. There is a golden rule for the hatching room temperature.If you feel comfortable inside the room temperature, the room has the proper temperature to operate an incubator inside it.
  • Power cuts can sometimes destroy a whole batch of hatching eggs.


Michael J. Mavridis D.V.M
CEO / Founder of Mavridis Zootechniki Ltd.
Web: www.eggincubator.eu
Email: eggincubator.eu@gmail.com