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Let’s start with how a mother duck would incubate her eggs in the wild.
In early to late spring a mother duck begins nesting. She will lay about a dozen eggs before she becomes broody. A “broody” duck is a female duck that is sitting on her eggs. She will stay sitting on the eggs for an average of 28 days.
During this time she will take short breaks periodically but will stay sitting on her eggs for a total of 20-23 hours a day. She will only leave for food and a quick dip in the water if the temperatures are warm enough.
There are many domestic ducks that do not go broody and will not sit on their eggs. This is completely normal. There are some breeds that are typically more broody but it will also depend on that specific duck. Just because Indian Runner ducks are typically non-broody, it doesn’t mean that a Runner duck would never sit on a nest of eggs.
How to incubate duck eggs using an incubator
Incubating duck eggs takes 28 days (35 days for Muscovys) once the eggs have “set”. The eggs are set once they have been in the incubator for 24 hrs.
Step 1 – Set the incubator
Before you place the eggs into the incubator you need to set the incubator. Be sure to watch it for a couple hours to make sure the temperature and humidity stay in the correct range.
I use (and recommend you do as well) a second thermometer to watch the temperature in different areas of the incubator. This ensures that the incubator thermostat is working properly and also shows if there are other areas that have a different temperature. If you look at the picture below you can see there is a additional thermometer and it says 99.9 but the incubator itself says 99.5. This difference stayed true for the entire incubation it would often fluctuate between .5 and 1 degree difference. Even though I rotated the eggs every other day or so, some eggs started hatching on day 26 where as the others did not start until day 28.
When using a homemade incubator I recommend setting and watching the temperature and humidity for 24 hrs. This is to make sure there is no big fluctuations during the day or night.
Temperature for incubating duck eggs
Although some people have successfully hatched ducklings at temperatures above and below, the recommended temperature is 37.5 °C (99.5°F).
Is it okay for the temperature to fluctuate?
Yes, the temperature can fluctuate a little bit. There are many factors that will say whether the fluctuations are okay or not. During the first week, any prolonged exposure to temperatures too high or too low for several hours will end up killing the embryos. If eggs that are closer to the end of incubation, and are exposed to the same amount of heat or cold, they would have a better chance of survival.
Brinsea Incubation Specialists speak about four different zones when incubating eggs. When eggs are in the over-heating range, which is at or above 40.5°C (104.9°F), for a prolonged period of time no eggs will survive.
The zone of hatching potential is between 35 to 40.5°C (84.5 – 104.9°F), with the ideal temperature at 37.5 °C (99.5°F).
The zone of disproportionate development is between 27 – 35°C (80.6 – 95°F). This zone can allow embryos to start developing but will be disproportionate and some parts will develop faster than others. When temperatures are below 35°C (95°F) it is not likely any embryos will survive.
And the last is the zone of suspended development (-2°C – 27°C/28.4 – 80.6°F). Eggs in temperatures below 27°C will not start developing; which is why when storing eggs prior to incubation the ideal temperature is 15°C/59°F.
Should you allow the eggs to have daily cooling periods?
Many people mimic the mother bird leaving the nest (when she searches for food) and allow the eggs to cool for a little while each day. All types of birds can benefit from cooling periods during incubation. Some people say for 30-60 min, others say 10-15 min is fine. If you choose to cool your eggs once a day you want the room temperature to be warm.
When the air is cold the mother bird will sit for the entire day and will not leave. However, on warm days she will spend extra time off the eggs to allow them to cool. So if it is warm in your room you can let them cool for up to an hour. The colder it is the less time I would give them, or even not at all.
When incubating ducks some people also mist the eggs after the cooling period. This mimics the mother duck coming back after being in the water. Misting duck eggs also helps to grow the air sac. As water dries on the outside of the egg, water also evaporates from the inside allowing the air sac to grow. Daily spraying can be helpful if the air sac is too small as you near the end of incubation.
Humidity for incubating duck eggs
Duck eggs need more humidity than chicken eggs and should be kept at about 55% (84.5°F on wet bulb thermometer). No need to panic if the humidity goes down or up a little. Do your best to try to keep it between 45% and 55%.
Just like temperature, humidity numbers can go up or down temporarily and still have a successful hatch. But, if they go up or down too much for too long it causes problems. Short spikes in humidity won’t harm the eggs. However, if the incubator was set to 80% humidity for the whole time the eggs would not get to hatch. If by chance the duckling did make it to hatch, it cannot unzip if the air sac is not big enough. The air sac cannot grow when the humidity is too high.
Having a lower humidity for a prolonged time during incubation usually poses no problem and will still give a successful hatch.
Some people have successfully dry hatched their duck eggs, which means they add no additional humidity until the hatch. This only works for those who live in a humid climate. If you live somewhere hot and dry they need the extra humidity or they can die. It is possible they may develop but hatching will be a struggle.
Step 2 – Set the eggs
Candle each egg and place the good eggs into the incubator. I use a high intensity flashlight but there are also specific lights called egg candelers if a flash light doesn’t work for you, or you’re wanting to set the egg down on the light to take pictures.
Do NOT place any eggs that are cracked into the incubator, even if it is a hairline crack and can only be seen through candling. According to this study, hairline cracked eggs have a significantly reduced hatch rate compared to eggs with no cracks.
Many people recommend not using oversized, undersized, misshapen, or double yolk eggs. They say not to use any “flawed” eggs because it reduces the chance of a healthy hatch. It does not mean that they 100% will not hatch, but they do reduce the hatch rate. I have heard of multiple cases where a double yolk egg was incubated and both yolks developed. In several cases they hatched into healthy (but smaller) ducks.
Lay the eggs in the incubator horizontal. If you are using an automatic turner (eggs placed vertical), be sure the pointy end is pointing down. If you’re unsure which end is the pointy end you can candle the egg. The air sac should be on the top.
Step 3 – Turning the eggs
Some incubators come with automatic egg turners, and others have ones that are an added accessory. The automatic turners help by turning the eggs from every hour to every couple hours for 24 hours a day. These are great for those that work long hours or just cannot be around to turn them that often. Some turners have the eggs placed upright to maximize space. Most experts recommend using a turner that allows the eggs to be laying horizontal, as it is more natural.
A warning of caution from a Brinsea Incubation Specialist:
“It is important to note that for both automatic and manual turning, the egg must not be turned in the same direction every time. If this occurs, the chalaza will wind up and eventually break, which causes embryo death. If you choose to manually turn your eggs, alternate turning direction in order to avoid this. If you choose an incubator with an automatic turning feature, make sure it turns the eggs in a random or alternate direction each time. Some incubators do not ensure this feature with their automatic turning, so that is an important detail to pay attention to.”
If you are turning the eggs manually
Mark the eggs with a pencil on both sides. It is strongly recommended to use only a pencil as the shells are so porous and can absorb anything on the outside of the shell. However, I have heard of many people using things like pencil crayon as well as markers. Crayons would not work well as the heat would melt the wax and prevent oxygen from getting through the shell.
Most people put an X on one side and an O on the other. It doesn’t really matter what you put, just as long as they are different. This is to ensure you are turning a full 180 degrees each turn and not forgetting to turn some.
You want to turn the eggs a minimum of 3 times a day, most people recommend doing 5 or 7 times a day. Just make sure you are turning an odd amount of times each day. This allows the egg to “sleep” on opposite sides each night. The embryo can end up touching, and attaching, to the side, when left too long in one position. This will cause the embryo to die. The yolk and embryo need to stay floating and moving.
Why is turning the eggs so important?
To help you understand why turning is so important we need to look at what happens inside the shell.
Brinsea Incubation Specialists explain what happens:
“As the embryo forms on the yolk, the yolk becomes lighter and lighter. This causes it to float upward in the egg. The yolk is somewhat held in place in the center of the albumen by the chalaza, but this twisted membrane — which serves as the rotating axis to keep the embryo on top of the yolk — only connects the yolk to the ends of the egg, not the sides. So, the yolk continues moving upward (toward the side that is on top, which in nature would be closest to the heat of the hen’s body).
If not turned for long periods the yolk will eventually touch the inner shell membranes. When the embryo touches the shell membranes, it will stick to the shell and die. Regularly turning the egg will prevent this, and ensure healthy embryo development. Another key benefit to turning your eggs is that by doing so, you are allowing the embryo to encounter fresh nutrients and oxygen inside the egg. Turning also moves metabolic wastes way from the embryo. This is especially important during the first week of incubation.”
When manually turning eggs, or any handling of the eggs, make sure you wash your hands first. Anything on our hands can transfer to the eggs, as they are quite porous. Any bad bacteria on your hands can get transferred to the egg. The bacteria can cause an infection inside the egg and will kill the developing embryo/ duckling.
Step 4 – Candling the eggs
To check for fertility, candle the duck eggs on day 7. If there are any eggs that do not have veins growing, look clear, or are cloudy, they are not fertilized and should be removed. While candling you may notice eggs that have no veins but has a dark ring, those eggs started developing but stopped.
I personally like to candle the eggs about once a week until they go into lock down. Using a pencil I mark where the air sac is. This helps to make sure they are losing enough weight and gaining enough air space for hatching.
If at any point you are unsure if the eggs are good or not just leave them and wait a week before rechecking. If they have not continued developing then you can remove them.
In the end you will figure out which ones were good as they will be the ones that hatch. If you have any that smell bad you need to remove them right away. Rotten eggs can explode in the incubator and can spread the bacteria to other eggs potentially killing them as well.
Brinsea has a PDF that goes into depth on candling chicken eggs, but the information is the same for duck eggs except for the numbers of days for development. Chicken hatch at 21 days and duck eggs hatch at 28.
Step 5 – Lockdown
When eggs are nearing their hatch date, they need to stop being turned. This allows the duckling to get into the correct position. This is why on day 25 of incubation the eggs are put into lockdown. If you have them in an automatic egg turner you want to remove them from the turner and place them on the floor (screen) of the incubator. If you are not using a turner then just stop turning them on day 25.
Ducklings can end up injured if they start hatching while still in the turner. They are not very sturdy when they first hatch and will scramble and flop everywhere for the first 24hrs or so before they gain the strength.
I had one time where a duckling started hatching before lockdown and I needed to get all eggs out of the turner. To prevent a major loss of humidity I boiled the kettle and placed it open beside the incubator. This helps to prevent too much moisture loss and lessens the chance of the hatching duckling getting shrink wrapped from a drop in humidity.
Humidity for Lockdown
Humidity needs to be increased to 75% at the start of lockdown. Many people increase the humidity in steps (55% to 65% for beginning of lockdown to 75% for once you see the first pip) but I find that you’re opening the incubator too much that way. And from speaking to others who have successfully hatched ducklings they increased the humidity at the beginning of lockdown and kept it at 75%. So you can get away with some flexibility in what you want to try and what works best for your climate. If your air in your house is naturally quite dry then you may want to keep it in the higher numbers to avoid shrink-wrapping.
Temperature for Lockdown
When you start lockdown, the temperature should also be decreased. You may notice that many people recommend different temperatures for lockdown. I’ve seen some people say they need to be kept at 36.6°C (98 °F). Others say 37 ° C (98.6 °F) and some even say 37.2°C (99°F). And they all say their temperature is the correct way to do it.
This just shows that there is a window of fluctuation where they will still successfully hatch. I choose to keep my incubator at 98.5 that way it is right in the middle and if the temperature goes up or down a little it will not affect the ducklings hatch.
Cornwall University College of Veterinary Medicine recommends lowering the temperature as they hatch so by the time they all hatch they are down to 36.1°C (97°F)
Incubating duck eggs using a broody duck
Some ducks go broody and will be happy to sit on eggs to hatch. You can just leave her to lay the eggs and do her thing or you can collect other fertilized eggs and add them to her nest. You can also add duck eggs to a broody chicken. Your climate, and how much humidity is in the air will decipher whether the ducklings will have a successful hatch or not. In a more humid climate they will hatch just the same as if it were a duck sitting. In a very dry climate they may struggle with hatching.
Mama duck (or hen) will know what to do and you can mostly leave her alone. But there are somethings you can do to help.
How to help a broody duck
Clean out the duck coop. You don’t want the ducklings running around in a dirty poop filled coop. Try to disturb mama duck and the nest as little as possible. When cleaning out the old bedding leave a buffer zone around the nest where you don’t touch that bedding. And If possible wait for her to leave the nest for a break before going in to clean it. This will cause the least amount of stress for her.
Candle the eggs after she has been sitting for 7-10 days. It’s best to wait until the evening so you can have a good view of the inside of the eggs. If there are any that are not developing take them out. Eggs that are rotten can ruin the whole nest of eggs, just like in an incubator.
Be prepared to create a space (where the other ducks can still hear and see but not touch) for the mama duck and ducklings to go to once they hatch, if need be. Sometimes other adult ducks can be a bit nasty to new ducklings. But then sometimes there are no issues at all. It’s just something to think about in case you need to take action. They will usually only need to be separated for the first week or so. Once they have grown and the other ducks should be fine with them. If you notice any of the adults picking on them you should separate a little longer.
Make sure there is water nearby as they are near hatching, as mama duck will show her ducklings where and how to drink their first sip of water.
What happens if you don’t check the eggs?
If you do not check and remove the bad eggs from the nest, or if you miss some, mama duck will usually kick some eggs out of her nest. If you were to crack them open you would see either unfertilized eggs or embryos that stopped developing. Be warned if you decide to open them and they have gone rotten they smell really really bad. So be sure to do it outside.
What do you do if 30+ days have come and gone and there is no sign of ducklings?
When she leaves the nest for food and water go and candle the eggs. You will be able to see if there is anything moving or alive inside. If you discover that none of the eggs will be hatching you can get some day old ducklings and place them in the nest.
If you leave the eggs in the nest for too long the eggs can explode. Rotten eggs are not something you want exploded all over the inside of your coop. So it’s best to remove them after you are sure none of them will be hatching. You may have a very sad duck for a little bit. But I have heard stories of ducks sitting for several months just waiting for them to hatch, which just isn’t healthy for them.
What do you do if mama duck is sitting on unfertilized eggs?
Most experts do not recommend allowing a broody duck to sit on eggs that will not hatch. It takes a toll on their body to sit for 30 days, as they only get off their nest to eat and drink for a short amount of time each day.
Female ducks that are going broody will stock up on food before sitting on the nest. They need to ensure they have enough fat on their body to last them all those hours when they do not go to eat.
Sometimes female ducks will go broody even if there is no male duck around, which means that all the eggs she is sitting on are not fertilized. You can, and should, break the broodiness. It may take a week and she will not be a happy duck. Eventually she will stop sitting on them if you make sure to remove the eggs every day.
If she does persist you may need to break up the nest daily as well. Some broody ducks may go a week without eating and focus on continuously trying to restart her nest. If you are persistent she will stop.
How to introduce ducklings to a broody mama duck
If you really want to allow her to sit on the eggs you should plan on getting a couple day old ducklings. Time it for around the time the eggs (if they had been fertilized) would have been hatching. Once she leaves the nest remove the old eggs, place a couple new eggs and the ducklings in the nest. You need to switch the eggs because they are all eggs that have no longer good. Eggs that will not be hatching will eventually go rotten and can explode.
Allow her a day with the eggs before you remove all of them. This will help keep her near the nest and help force a relationship with the new ducklings.
Try to keep a close eye on them without disturbing mama duck. You want to make sure that she is showing them where the food and water is and allowing them to come in close for warmth. It can take several hours for her to fully accept them so it’s best to block off the nest and mama duck from the rest of the flock until they have bonded and she has accepted them.
To sum it all up
It does not matter which way you choose to incubate duck eggs. You could buy a super expensive automatic everything type incubator, you could make something yourself, or have a broody duck do it for you. It does not matter as long as they have the correct range for heat and humidity as well as being turned. I have a family friend who incubated duck eggs on a cushion under a regular incandescent bulb and they successfully hatched. She lives on the west coast of Canada where it is very humid so humidity was not an issue.
So it just shows that incubating duck eggs does not need to be a super scientific thing. You just need to meet the basic needs of temperature, humidity, and turning.