How to incubate fertile eggs
Steps for success
A quick reference guide to incubator hatching of fertile duck eggs
Start your incubator 3 days before you add eggs to troubleshoot. Temperature should reach 99.5F and stay there consistently. Humidity should be as close to 50% consistently. After you’ve used your incubator several times, you can start it the day before. Some incubators need to be factory reset every time you start a new batch - see the manual. A separate temp/humidity gauge is very useful to make sure you’re hitting targets for both - my preference is a Bluetooth meter that sends the readings to an app on my phone.
Make sure your eggs are unwashed, fresh (no more than a week since being laid) and fertile. If they are very dirty, scrape the dirt off gently and only enough to where the egg can “breathe” - do not wash the egg with liquids.
Shipped eggs should be padded, not bagged or sealed. Eggs should be stored and shipped with the bigger side up, pointy side down. Open the package immediately to check the eggs, but DO NOT handle the eggs. Allow them to sit pointy side down for 2 hours at least to settle and come to ambient temperature after being shipped. If any are cracked or broken, remove them and as much of the liquid as possible without disturbing the good eggs. Small cracks can be sealed carefully with a same-size covering of melted wax, but these eggs will have less of a chance of developing successfully.
One by one, remove each egg, unwrap and inspect it. Mark each egg individually (number/letter) on a side with pencil or very fine marker. You can candle the eggs before putting them in the incubator to check the shells for cracks. Mark, candle, then set the eggs beside the incubator before opening the lid to avoid heat loss until they’re all ready. Set them inside on their sides and inside a turning tray slot, unless you aren’t turning or doing it manually. The marks on the eggs should help you see that they are being turned. Almost every time I start a batch, a few hours after setting the eggs my incubator will beep a low-temp warning. This is simply the warm, empty incubator struggling to fully warm the eggs inside and takes several hours to achieve - this is completely normal and everything’s fine.
Once the eggs are inside, keep temp/humidity consistent and lid closed for one week. Candle to check development. Duck eggs take 28+ days to hatch out, so only candle once a week unless you’re in a classroom setting. Always get everything ready before opening the lid to minimize the time the eggs are chilled and heat/humidity loss from the incubator. In a natural setting, mom gets off the eggs for a few minutes a day until they get close to hatching. Developing eggs should have a distinct air sac at the bigger end and veins/embryos. Closer to hatch, the air sac will be about 30% of the egg, the duckling will look very dark and might be moving. Remove any quitters (embryos die and stop developing), rotten eggs (they can have bacteria inside and you don’t want these exploding) or infertile eggs that never develop and throw them away.
When hatch time gets close (~day 25), stop turning the eggs, temp remains at 99.5 and humidity should be increased to 65%. During candling you can see shadowing (the duckling presses against the internal membrane), internal pipping (the duckling pokes through the internal membrane and begins breathing from the air sac), and external pipping (the eggshell develops a circular crack and eventually the external membrane will be opened under the crack). Do not handle the egg after external pipping, only candle by putting the light source against the egg in the incubator if needed. Hatching starts with a round break in the eggshell, followed by a tear in the external membrane under that crack, zipping where the eggshell breaks all around into rough halves, and finally the duckling hatches by struggling out of the eggshells. You can hear peeping at this stage and the eggs will rock back and forth as the ducklings move inside. Talk to the eggs at this stage - this is when the duck will communicate with her babies so they recognize her after hatching. Be patient during the phases, as sometimes over a day can go by without apparent progress while the ducklings rest.
DO NOT remove ducklings from the incubator after hatching. Allow them to dry (they will look fluffy), stimulate the other ducklings to hatch (they will move around and roll eggs, that’s normal) and keep the heat/humidity even inside the incubator. Hatching eggs will increase the humidity in the incubator, this is normal and can be adjusted by opening all vents to keep it around 60%. Hatchlings absorb nutrients during the hatch phases and can survive for a day without eating or drinking. Only move ducklings to a brooder in groups, so they don’t stress by being alone and can keep warm. If you need to open the incubator for any reason, have help and move fast (one person controls the lid, the other grabs chicks and empty shells). Chicks can bleed from their umbilicus (belly buttons), so they need to be removed and cornstarch applied to stem the bleeding.
Incubator deep clean by disassembling, disinfecting, cleaning with a soft cloth and fully air drying before storage or the next round of eggs. Happy hatching!!