How to Hatch Eggs

Hatching eggs can be a very rewarding experience and many beginners are buying incubators since they have become far more affordable over the last few years. The main manufacturers for the hobby market seem to be R-COM and Brinsea Incubators and both produce an excellent range that can accommodate 20 to 25 chicken eggs, perfect for the beginner to hatch their own eggs!

Before you start

Before you incubate and hatch chicks, you should remember that you will end up with a ratio of half male and half female chicks. Unless you are hatching an autosexing breed (where markings or colour of the chicks are different colours) or have crossed two birds that give a sex-linked chick (again, different down colour or markings) then you will need to think ahead  to when the young growers can be sexed around 8 weeks of age and consider what you will do with the excess of male birds. Sadly, they are very hard to re-home, everyone has the same problem: too many boys.

Choice of incubator

incubator

The R-Com Suro is a forced air incubator that controls both temperature and humidity.

There are essentially two types of incubator –still air and forced air. The big difference between the two is the forced air uses a fan which circulates the air inside. When you measure the temperature, it should be the same throughout. The still air incubator has a temperature gradient inside so the hotter air rises to the top and there can be several degrees difference between top and bottom. For the average beginner wanting to increase the size of their flock, a forced air incubator is in my opinion the best choice. If you can afford a model that has automatic humidity control then you should have far more success than setting and maintaining the humidity control on a manual unit.

Incubating Chickens Eggs

Chickens eggs have a 21 day incubation period (isn’t that amazing? Egg to chick in just 3 weeks!) and require a constant temperature of 37.5°C. Eggs will start to produce their own heat in the latter stages of development but the incubator thermostat takes care of this, keeping the temperature the same throughout the incubation period. Humidity should ideally be between 45 and 50%. Eggs need turning regularly by 180 degrees and you will need to do this yourself if the incubator doesn’t have an automatic turning mechanism. Expect 50% to 75% of your eggs to hatch, not all eggs will be fertile.

Hatching Eggs

Eggs need to be fertile so a cockerel needs to be running with the hens for a few weeks before eggs are taken for hatching. If you have a cockerel, you can collect your own hatching eggs from your chickens. Try to pick good looking ‘egg shaped’ eggs, this will help the chicks form and hatch correctly as mother nature intended. Keep nest boxes clean and don’t set any soiled eggs. If you don’t have a cockerel or would like a different breed, there are many hatching eggs for sale online on sites such as eBay but keep in mind that just about anyone and everyone sells eggs so birds vary in quality between sellers. Hatching eggs travelling through the postal system can be damaged internally and either not develop or die before they hatch. These are often called dead in shell.

Incubation tips:

  • Before you put your eggs into any incubator, make sure it has been sterilised with an incubation disinfectant (or as a minimum warm soap and water if you don’t have this). This will kill bacteria that multiply rapidly in the warm temperature of the incubator.
  • Plug in your incubator and make sure the temperature is steady at 37.5°C. Always leave it to run overnight to settle before putting eggs in.
  • Keep water reservoirs topped up so that adequate humidity can be maintained at all times.
  • Candle eggs before putting them into the incubator. Cracked or damaged eggs do not hatch and should be removed after candling (see below for more information on candling).

Candling Eggs

candling

Candling an egg in the dark using a special candling torch. Blood vessels and the embryo can be clearly seen after a week.

Fertility of eggs cannot be determined before incubating them. It is easiest to see development of the embryo after a week. The most critical period of incubation is the first week so if you do decide to candle your eggs before a week then be very careful with them and do not overheat them. Eggs with blood rings, cloudy eggs or clear eggs (infertile) should be removed when detected. The photo to the right shows an egg that was candled after 8 days. If you can’t see much, do this in the dark. It may also help to tip the egg gently from side to side so you can see the inside of the egg moving and see what are patches on the egg shell and what is inside. The developing spider like veins and a small dark embryo can be seen. If you look carefully and have a bit of luck with the positioning of the embryo, you can often see a small heart beating away. I usually candle after 7 days and again at around 14 days. There is more information on a separate page about candling eggs.

The Air Sack

An Air Sack is formed at the broad end of the egg shortly after an egg is laid. There is a membrane between this and where the chick is developing. When candling periodically through the incubation period, this is the best method of judging normal development and you will see this increase in size up until the point that the chick breaks through into this air sack.

The Hatch

  • A chick will usually ‘pip’ the shell a few hours after breaking into the air sack so she can breathe but a full hatch can take 12 or more hours from this point so be patient.
  • If humidity has been set too high during the incubation period, the chick may pip the shell underneath the shell and drown in the fluids before he can get his beak out of the shell.
  • If the humidity has been too low, the air sack will be too large and the chick will be under-developed  and may become stuck to the shell, too weak to break free.

If a chick has pipped but does not make any progress, wait 12 hours, then consider breaking the top part of the shell away (but no more…) Some say do not help weak chicks as you are breeding weakness into your flock but there are many reasons why eggs don’t hatch. If it is a humidity problem like this or the line is particularly in-bred (often found with exhibition strains) then a little help can usually be given without detrimental effect.


The film above is speeded up and shows the final moments of a Copper Black Marans egg hatching in an RCOM King Suro incubator. As you can see with the King Suro, there is a good viewing window to see what is going on! It is my favourite incubator and is incredibly well priced.

And finally…

  • Do not remove hatched chicks until they are fully dried out. Chicks do not need to eat for 24 hours. This is why they can be shipped around commercially as ‘day old chicks’.

Good luck with your hatch!

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Do you have any tips on hatching eggs? Please leave me a comment below.

51 Responses to How to Hatch Eggs

  1. sarah says:

    My mum is in the middle of a power cut and she’s wondering if eggs will hatch if they haven’t had heat for 12 hours?

    • Keeping Chickens says:

      They might, cover the incubator to keep the warmth in and hope for the best!

    • Matthew says:

      Yeah, Just resume incubating as soon as possible. The embryos can actually take a pause in incubation for a while without to much harm being done. Good Luck!!

  2. welcome says:

    hi ,as a starter with a 1000 eggs aeromatic incubator i have just got, can i put inside 500 eggs insde when i havent got enough eggs ?

  3. welcome says:

    I stay in Peddie in the Eastern Cape .Can anyboby advise me where to purchase fertile eggs for large chickens as I want upgrade the quality of chickens . Such as astrolope and others pls. I would like to join the club of chicken growers if there is any .

  4. AH says:

    Have a hen sitting outdoors on one egg for about 8 days. Scuffle with another hen cracked egg, water dish dumped onto the depression in the dirt where egg lay & was hen sitting. I picked egg up out of water. Inner membrane appeared to be intact. Hen came right back to it, eventually pushed egg back into depression (pool of water had drained). Do I need to attempt to repair crack with glue-wax-nail polish? Or can hen sitting on it protect it sufficiently?

    • Keeping Chickens says:

      I don’t know, I haven’t ever done this before.

      The broody should be separated in her own house during this time because other hens will disrupt her and will peck the chicks, causing them severe damage or even death.

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