khaki campbell ducklings hatching              chicks4


The process that a hen does so easily and so effortlessly three times in a year, is very difficult to replicate. I have a healthy respect for a hen when I know how much I have struggled to incubate!

Incubation means the developing of an embryo within a closed sphere, that is your machine.

Incubation of chicken eggs is a 21 day process. Within the first seven hours, you have a heart beat and blood vessels forming.

Within 24 hours you have eyes starting to form and a working heart. After this, the babies form slowly until the feathers, the nails, the legs are the last to form. The last part of the process is the absorption of the yolk, which usually happens on the last two days.
Candling, or shining a light into the egg to check development is a good way to see if the embryo is developing correctly.
Try not to candle before 7 days as before that the blood vessels are very delicate and could rupture.
Check the development of the air sac, according to the diagram.

air sac2
If your air sac is too large, it means you have too little humidity.
If the air sac is too small, your humidity is too high.
Any clear eggs should be discarded so that they don’t explode in your machine.
If you do not have an automatic turner in your machine you need to turn the eggs at least 3 to 5 times a day, always uneven numbers so that the eggs do not always spend the night turned the same way, as presumably you will not turn overnight. Handle gently . If you observe how gently a hen turns her own eggs it might give you a few pointers!
When turning gently turn from side to side, NEVER from end to end as you risk twisting the umbilical cord.
Always have clean hands when turning the eggs, as oils and dirt from your hands can block the pores of the eggs and prevent oxygen reaching the embryo.
Oxygen is vital at all stages of development:

  The essential exchange of gasses between the embryo and the air sac, oxygen and C02 is vital to the correct development of the embryo.
Therefore you need an incubator that has a fan which will circulate warm air around the machine. The air needs to circulate inside the machine, not be drawn in from outside. This is very important, as in most machines there needs to be an inflow of fresh air from outside. In an incubator this is bad. Your incubator needs to be an all in one enclosed artificial hen, that will incubate your eggs. When you open the box to turn the eggs always switch the fan off and allow the air to be renewed inside the box while you turn your eggs. This is sufficient fresh air.
Your humidity needs to be as follows:
chicken eggs: start with low humidity to allow the blood vessels and heart to form first.

20% is plenty from day one to day five.
On day 5, you can increase to 25%. On day seven again to 30%. On day 10, increase to 40 %.
On the last two days of incubation increase to 55%.
This is of course different for all climates: In very humid areas, you may need to reduce humidity. In very dry areas, you may need to increase.
On day 19, take the eggs out of the turning section and lay flat in a hatcher.
Do not turn again, and do not open the incubator.
Do not be tempted to help the chicks out of the egg unless you see visible signs of prolonged distress, usually due to insufficient humidity.
In that case , remove the victim, and in a bowl of warm water, hold the egg so that the head of the chick in the air sac, is not submerged, and slowly peel the egg away from the head and body. Leave the bottom section alone, return to the incubator.
All your eggs should hatch within a 24 hour period. If after this time has elapsed you still have eggs in the tray, remove them, candle them and see if the babies are still alive.
If you see signs of vigorous life, leave the eggs in the tray, and wait. Any dead embryos must be removed from the incubator.
If you are not sure, have a bowl of warm water, about blood temperature on the side and place the egg, air sac uppermost in the bowl.
wait a while for all water movement to stop and see if the egg itself is moving or bobbing by itself. If it is, the embryo is still alive.
If there is no bobbing, the chick has died, for whatever reason.
There is sometimes a time lapse between the first hatching eggs and the last,  when eggs are:
1. too large
2. From older parent stock.
3. Of specific breeds that are not genetically strong or robust.
4. Eggs that have been in a part of your incubator that has cold or hot spots, and therefore the egg does not progress at the same rate as other eggs.
Sometimes this is a waste of time but occasionally you get your next champion from having patience and waiting it out. It is a question of personal choice.

Remember that different breeds hatch at different times. There is no reason for this, just genetics.


This is difficult to determine but here are some guide lines.
1. If the chicks that hatched battled to come out of the egg it could be there is not sufficient humidity in the box.
Chicks need plenty of humidity in the last few hours, to be able to turn inside the egg.
2. If the chicks hatch but are weak, it could be there is not sufficient oxygen and CO2 exchange in the box. There needs to be sufficient oxygen flow in the incubator to allow free exchange of these two gasses from air sac to the outside.
3. If when breaking open unhatched eggs you see a lot of water, the chick has drowned because of too much humidity in the box and not enough air flow. You may get this if you use a Styrofoam incubator.
4. If your embryos are dying before hatching, in the first seven days, this could be due to rough handling before or after setting.
5. If the chicks are dying at the end of the hatch cycle this is probably due to weak genetic material in your breed pen, or lack of correct nutrition in the parent stock. Remember that incubation does not start in your box, it starts generations before in the grandparent, parent stock, feeding, health of stock, lack of parasites, environment and lastly the breeding set up as male to female ratio etc.
6. Check your incubator for cold or hot spots, and whether the heat is constant. You should be between 99 3/4 degrees F and 100 degrees F.
There should not be more than one degree offset temperature between maximum and minimum at any time.
Check the turning mechanism, or if you turn by hand how are you doing this? It must be side to side GENTLY, at least 3 times a day. Always turn an odd number of times as you do not want eggs staying on the same side night after night.
Always ensure your hands are clean and free of any oils that might clog the pores on the outside of the eggs.
Make sure you set only clean eggs, with no visible cracks or flaws,  to avoid contamination from bacteria, which thrive in the humid warmth of an incubator.
Many chicks in unclean incubators will die of omphalitis, an infection due to bacteria found on unclean eggs or unhygienic incubators. This disease is also knows as mushy chicks because the chicks are very wet, smelly and usually with unabsorbed egg yolk after day 21.
Disinfect your incubator after each hatch.
7. If you do get unabsorbed egg yolks, this could be due to bacteria or due to too much humidity and insufficient air flow in the box.
8 Bloody navels usually mean the temperature in the incubator is too hot. Chicks usually hatch early because of this.
9 Late hatch could mean the temperature is too low, or constant power failures!

10. Embryos that die at day 7 to 14 days incubation, and show a distinct blood ring on one side of the egg, indicate the egg was not turned properly, turned too roughly, turned end to end instead of side to side, or not turned enough. If turning by hand mark your eggs with an” X” on one side in pencil and a “0” on the other, so that you know you have turned every single egg. Eggs must be turned at least three times a day.

Power failures in the hatching cycle between days 7 and days 18 are not serious as the chicks will go dormant and will hatch late, but will hatch. Power failures before day 7 and after day 18 can be disastrous.

If you have glass water bottles on tap and a gas cooker you can fill several hot water bottles with boiling water, wrap a towel around the bottle and leave the hatching eggs inside the towel. Replace the hot water bottle when cool. Don’t use plastic bottles which may rupture and flatten out with the heat.


Imported Natureform incubator 270 eggs plus hatcher.


That is like asking what underwear you prefer. It is a personal choice, based on your finances, your needs ( you may want a 50 egg machine or a 20,000 egg machine), whether you are commercial or a hobbyist, and also what climatic conditions you enjoy where you are.

My suggestions are these:

1. Determine what needs you have. Are you going commercial or hobby? Do you want to do multiple stage or one stage incubation? Are you interested in automatic or manual turning?

You need to ask yourself this before you buy, because there are many machines out there and you must end up with one suited to you. It is no good ordering a 4000 egg incubator and then asking everyone around you for setting eggs because you cannot fill your machine. That is a waste of time, money and effort. You end up with rubbish birds that you then have to feed, and it is expensive. A large machine costs a lot to run, and if you want to fill it, which is the only way it will make money for you, you need to have the parent stock to lay those eggs, and have a ready market to sell the chicks. So do the maths first not last.

One hen can only lay one egg a day, and sometimes wont lay. Are you prepared for that?

2. Determine what brooder and rearing space you have. Chicks need warmth, a heat lamp, a safe area to grow away from predators, feed and water, someone to change the bedding and water and feed them. Bedding itself can be costly so can the cost of heating.

3. Make sure you have all the equipment you need to run your incubator: If it requires a water source, you need one close by. Make sure the thermostat is accurate and works. Make sure you have a hygrometer and an accurate thermometer to check temperatures and humidity. Make sure the room you have chosen is cool, well ventilated but away from cold draughts.

4. Find out if the incubator you have has a hatching tray, or you may need another incubator to act as a hatcher. It is a risk to incubate and hatch in the same machine but sometimes this is unavoidable.

5. Ensure that your machine is working correctly BEFORE you set eggs. have the machine working 24 hours empty to check temperature, ventilation, humidity.

6. Make sure you have cleaning agents on hand to disinfect your machine between hatches.

Now that you have done all of this what is next?


Select the eggs you are going to hatch and put them aside in cardboard boxes. Never use polystyrene as the eggs sweat and bacteria builds up on the outside of the egg. Remember an egg is a semi permeable membrane, anything can go in, nothing comes out. Make sure eggs are of uniform size, not too large or too small, never cracked or very dirty.

Don’t keep setting eggs longer than 7 days, and make sure while waiting to go into your machine you turn the eggs twice a day, side to side. Easier to turn the boxes on their side and turn the boxes side to side twice a day. Mark each egg with pencil with the date of collection, and the pen number or ring number of the hen that laid the egg. Keep the setting eggs in a well ventilated area, cool but not cold. You need to turn the eggs even before you set them twice a day to prevent the yolk from sticking to one side or the other of the membranes. Lay your cardboard boxes on their side, with the eggs inside, tilt every day side to side twice a day. Never store hatching eggs with the pointy end up, always store with the air sac, or round end uppermost. Handle CAREFULLY. I cannot stress this enough. Rough handling or bumps and knocks will kill the fragile embryo before it has a chance at life.

On setting day, do not turn your eggs for the first 24 hours.

egg 20140002chicks4


Clean eggs. Eggs mostly the same size. Discard eggs too large, too small or double yolked.

Temperature of the incubator.

Humidity of the incubator.

Air flow of the incubator.

Turn eggs three time daily.

Stop turning day 19.

Make sure chicks are placed in a warm brooder with feed and water.




  1. The first cycle is day one to seven, when the embryo begins to form. You will see a distinct air sac in the egg and a tiny little red dot in the middle of a slightly off centre yellowish ring. This is the embryo beginning to develop and a beating heart, visible from 24 hours of incubation. From day two you will see the distinct “spiderweb” of blood vessels which should be a healthy red colour and which show incubation is working correctly. If the spider web is dark, or even worse a ring of dark blood is visible inside the egg, the embryo has died and the blood has been drawn to the outside . From day two and three you may see an umbilical cord beginning to which the embryo is attached. From day five you may see eyes. From day six to seven you may see the beginning of a curled embryo with a head and eyes.
  2. The second cycle is from day seven to fourteen. After day seven it is generally safe to remove the eggs from the incubator and candle them. You may see the umbilical cord and a small embryo attached from it and moving vigorously. The air sac is now larger and provides a good supply of oxygen to the chick. From day eight to ten you will see a growing chick inside the egg, with a distinct head and beak, swinging wildly inside the growing medium of egg white.
  3. The third and final cycle is from day fourteen to twenty one. The chick begins to fill the egg and movement is slower and more restricted as the chick runs out of room. You will see a curled embryo, curled into a ball, the head tucked inside the wing, feet now visible. The yolk is tucked within the curled body and the umbilical cord is attached from the yolk to the chick. The air sac is now quite large. On day eighteen to twenty, you will see the chick begin to peck through the membrane of the air sac, but it has as yet not broken through to the outside. at this stage the embryo is dormant, the beak is through the air sac and the chick begins to breathe air. This is called pipping. You may hear cheeping from inside the egg. By now the chick is absorbing the egg yolk as its first meal. On day twenty one, the chick begins to peck through the outside egg shell with its egg tooth, and a small flap of shell is lifted. After this the chick will turn within the egg and peck its way all the way around the egg until it can with its strong legs, kick the top of the shell away and struggle out of the egg. It is important for them to do this on their own, as kicking their way out is the way they strengthen their legs, straighten them and allow the lungs to expand for its first outside breath.


Embryonic Development, Day by Day

01 July 2009


By Dr Stephan WARIN, DVM, Avian Business Unit. Ceva Santé Animale, La Ballastiere, BP 126, 33501 Libourne Cedex, France

Unfertilized egg: The embryonic disc of a sterile egg bears an accumulation of white material at its center

Fertilized egg: The fertilized embryonic disc looks like a ring: it has a central area, lighter in color, which is to house the embryo.

Day 1: The germinal disc is at the blastodermal stage. The segmentation cavity, under the area pellucida, takes on the shape of a dark ring.

Day 2: Appearance of the first groove at the center of the blastoderm. Among extraembryonic annexes, appearance of the vitelline membrane which is going to play a major role in embryo nutrition.

Day 3: The embryo is lying on its left side. Onset of blood circulation. The vitelline membrane spreads over the yolk surface. The head and trunk can be discerned, as well as the brain. Appearance of the cardiac structures which begin to beat.

Day 4: Development of the amniotic cavity, which will surround the embryo: filled with amniotic fluid, it protects the embryo and allows it to move. Appearance of the allantoic vesicle: it plays a major role in calcium resorption, respiration and waste storage.

Day 5: Sensible increase in the embryo’s size; the embryo takes a C shape: the head moves closer to the tail. Extension of limbs. Differentiation of the fingers of the inferior limbs.

Day 6: The vitelline membrane continues to grow and now surrounds more than half the yolk. Fissura between the first, second and third fingers of the upper limbs, and between the second and third fingers of the lower limbs. The second finger is longer than the others.

Day 7: Thinning of the neck which now clearly separates the head from the body. Formation of the beak. The brain progressively enters the cephalic region: it progressively grows smaller proportionally to the embryo’s size.

Day 8: The vitelline membrane covers almost the whole yolk. Eye pigmentation is readily visible. The beak’s upper and lower parts are differentiated, as well as the wings and legs. The neck stretches and the brain is completely settled in its cavity. Opening of the external auditory canal.

Day 9: Appearance of claws. Budding of the first feather follicles. Growth of the allantois and increased vascularization of the vitellus.

Day 10: The nostrils are present as narrow apertures. Growth of eyelids. Extension of the distal portion of the limbs. The vitelline membrane completely surrounds the yolk. Feather follicles now cover the inferior part of the limbs. Appearance of the egg-tooth.

Day 11: The palpebral aperture has an elliptic shape that tends to become thinner. The allantois reaches its maximum size while the vitellus begins to shrink. The embryo now has the aspect of a chick.

Day 12: Feather follicles surround the external auditory meatus and cover the upper eyelid. The lower eyelid covers two thirds, or even three quarters, of the cornea.

Day 13: The allantois shrinks to become the chorioallantoic membrane. Appearance of claws and leg scales.

Day 14: Down covers almost the whole body and grows rapidly.

Day 15 & 16: Few morphological changes: chick and down continue to grow. Vitellus shrinking accelerates. Progressive disappearance of the egg white. The head moves toward pipping position, under the right wing.

Day 17: The embryo’s renal system produces urates. The beak, which is under the right wing, points to the air cell. The egg white is fully resorbed.

Day 18: Onset of vitellus internalization. Reduction in the amount of amniotic fluid. This is the time for transfer from incubator to hatcher, and also perhaps in ovo vaccination.

Day 19: Acceleration of vitellus resorption. The beak is against the inner shell membrane, ready to pierce it.

Day 20: Vitellus fully resorbed; closing of the umbilicus. The chick pierces the inner shell membrane and breathes in the air cell. Gas exchanges occur through the shell, which is porous. The chick is ready to hatch. Piercing of the shell begins.

Day 21: The chick uses its wing as a guide and its legs to turn around and pierce the shell in a circular way by means of its egg-tooth.

It extricates itself from the shell in 12 to 18 hours and lets its down dry off.




One thought on “INCUBATION

  1. Pingback: EGGS | Chicken Wired

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