Hatching Do's and Dont's - Egg Selection, Handling and Incubation Tips

Hatching chicken eggs in an incubator (or under a hen) is very simple, as long as you follow a few basic guidelines.

While it may seem to be a very easy process, small variations in egg handling, temperature or humidity can cause your eggs to not hatch, or to not hatch into healthy chicks.

Follow these simple DO's and DON'Ts to achieve the best hatch rate possible.

What happens before you even start to incubate the eggs can be just as important as your incubator temperature and humidity. So for an optimal hatch rate...

-DO choose the freshest eggs you can. Eggs retain good fertility for about 7-10 days, then it drops dramatically. You can collect eggs for about a week and then set them, but I wouldn't wait longer than that to pop them in the incubator.

-DO choose the most 'normal' eggs to set. Pass on any overly large or very small eggs, or those that are misshapen or otherwise 'wonky'.

Small pullet eggs often don't allow enough space inside for the chick to develop, large eggs are often double yolkers - meaning two chicks could develop.

Sometimes they both make it, but often, again there's just not enough room inside the shell for both chicks to develop correctly.

-DO choose the cleanest eggs you can. Washing hatching eggs is not recommended because each egg is coated with the natural 'bloom' which works to keep air and bacteria out - very important when you're hatching eggs.

If need be, flick any dirt or poop spots off with your fingernail or a rough cloth, but remember that any dirt on the eggs will introduce bacteria to your incubator.

-DO store eggs with the pointy end down at a 45 degree angle. While you're collecting eggs to hatch, store them this way so that the yolk remains centered within the shell.

Turning the stored eggs a few times a day side to side can also help your hatch rate, because that prevents the yolk from sticking to the shell.

-DO store eggs in a cool place around 60 degrees. Refrigerating hatching eggs can cause them not to hatch, and storing them in a warm place can cause them to start to develop, so keep them nice and cool until ready to set them, maybe the garage or basement.

-DO let the eggs come to room temperature and preheat your incubator before starting. Putting cold eggs into a hot incubator can cause condensation to form on the outside of the eggshell, which you want to avoid because that not only removes the bloom but increases the humidity inside the incubator.

So let the eggs warm up a bit before setting them.

-DO candle the eggs before setting them. Discard any eggs with any hairline cracks in them. Or you can try to seal small cracks with melted beeswax.

-DO set your incubator out of direct sunlight. Overheating for just a few minutes can kill the embryos, so locate your incubator in a room where it isn't directly in front of a window.

-DO put the incubator out of reach of pets or children and teach kids not to touch the eggs or the incubator.  Obviously eggs break easily, so they shouldn't be handled during the incubation period except to candle them (I usually candle on days 4, 7 and 18).

But also each time the incubator is opened, the temperature drops, so you want to avoid unnecessary handling of the eggs and the incubator settings shouldn't be fiddled with either. 

-DO remove any eggs that start to 'weep', turn black or smell. That indicates that bacteria has gotten inside the shell, and contaminated eggs sometimes explode, ruining the other eggs.

(Evidence of a 'blood' ring, literally a reddish circle inside the egg when you candle, is also evidence of bacterial contamination.)

And now for a few dont's:

-DON'T use eggs older than 2 weeks. You'll likely be disappointed with your hatch rate.

-DON'T choose extremely small eggs, or eggs from a brand new layer. A small egg might not allow enough space for the embryo to develop correctly.

It's generally thought that a better hatch will result using eggs from hens that have been laying for at least a few months, and preferably a year.

-DON'T choose dirty eggs - and don't wash the eggs you plan on setting.  The cleaner the eggs, the better chance that no bacteria will get into them.

Bacteria that manages to get through the pores in the eggshell will will the growing embryo.

-DON'T set your incubator in direct sunlight. You want the temperature to stay constant inside. If the temperature changes by just a few degrees, that can delay your hatch (if the temperature falls to low) or kill the embryos (if the temperature rises too much).

-DON'T put the incubator where it can be knocked over or fiddled with by kids or pets.  Hatching eggs are very fragile and should be handled or jostled as little as possible.

Follow these simple tips and your hatch should go off without a hitch.

As for temperature, egg positioning and humidity in the incubator, follow the instructions for your specific model.  For a detailed day-by-day hatch tutorial using my Brinsea Mini Advance, read HERE.

Get everything you need to hatch chicks from our friends at Brinsea!

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  1. I've read on a Chicken site 101-102 is best for hatching...what if you follow that rule. The eggs didn't really seem that warm to me....If I candle at day 7 or 8 and all I see is yolk, that means I must discard or wait a little while? This is my first time incubating and they have been in for 6 days. Thanks

  2. Unless they're weeping, I dont throw anything out before 14 to 18 days.

  3. Also, 99 to 100 if your incubator has a fan. 101 if it doesn't.

  4. You should follow the instructions for your own particular brand of incubator and set the temperature accordingly. I agree with Cindy - don't be too hasty to toss any out you think aren't developing.

  5. Is it true that the temp of the incubator can determine the sex of chicken? I ordered 12 fertile eggs, on 6 hatched but 5 of them turned out to be roosters. I had the incubator at 100

  6. I have never heard that of poultry, just reptiles!
    Temp in croc and geckos determines gender

  7. I am still planning to let Hazel, my hen that gets broody each spring, hatch some babies this year. I have a couple of different people who have offered to give me some fertile eggs. This post will be a great resource for me when the time comes!

  8. I've heard that but don't believe it. If it were true, all the hatcheries could just hatch females. Which they can't.

  9. We used to raise laying hens and out 60,000 per year we would only get 10 to 12 roosters.

  10. That is reptiles that temp can determine sex... Temp with circulated air 99.5 higher for still air. See backyardchickens.com

  11. There is so much assistance on backyard chickens.com

    Do you have a still air or circulating incubator? Be sure your thermometer is correct and have at least 2 and verify hygrometers. Silly question: Are you sure you have fertile eggs?

  12. Oh its super easy tho when a chicken does it. She handles everything!

  13. Thank you for this article! We are just getting ready to put some eggs in an incubator to hatch for the first time (or other chickens were purchased as baby chicks). We are very excited to see if it actually works!

  14. Ok question.. Iv had my eggs in since the evening of march 22. Today I checked on them and dropped one and it broke. And I opened it and all I see was yoke and a small baby with eyes but it wasn't even the size of my finger nail but it had eyes.i could tell that. What's that mean? Shouldn't it be a complete developed chicken by now. My boyfriend broke one a week ago and said it was the same way. What am I doing wrong and when should they hatch?

  15. Day 21 one pipped and hatched on day 22. Of 41 eggs, 21 were ok via candling.CM couldn't tell so kept, Jubs looked good CLB via Ebay no. Only one CLB looked good out of 12. Day 22 nothing, day 23 nothing. day 24-25 turned off incubator, placed unhatched eggs in ziplock and opened...perfectly forms babies with an unabsorbed yolk...day 17-18 in development so at lockdown they died? I'm so sad about this. TS incubator with turner..Opened lockdown to increase humidity...60% was max...what went wrong?