deficiencies in the breeding stock.
If you have your own fertile eggs (laid by your own ducks), pick those that are most perfectly and uniformly shaped, preferably not covered with mud or manure. Don’t wash them; instead, carefully scrape off any muck with your fingernail or a rough sponge. Don’t choose overly small or large eggs because they tend to not hatch well.
Before you turn on the incubator
While you’re collecting enough to fill your incubator, store them, pointy end down, at a 45-degree angle in a cool location – around 60°F is optimal. Don’t turn on the incubator yet! Rotate the eggs side-to-side several times a day to keep the yolk centered in the white. Hatchability declines each day after an egg is laid. Fertile eggs will stay viable for about a week after being laid. After that, fertility starts to decline, so try not to delay setting the eggs for too long.
“Candling.” “Candle” each egg one by one, whether you are collecting your own or you ordered shipped eggs. Candling is so called because in early days before electricity, the light from a candle flame was used to check for cracks, and later during the incubation period to “see” inside the egg to monitor development. You are checking for hairline cracks. You can use a regular flashlight – no need to use candles any longer! Cup your hand around the beam to shine it through the shell, or buy a commercial egg candler. Discard any cracked egg or seal minor cracks with softened beeswax to prevent bacteria and air from entering the egg through the crack and killing the embryo.
Check for cracks in the shell using the “candling” method.
In the incubator
When you are ready to set your eggs, turn your incubator on and let it get up to temperature while you let the eggs sit for several hours at room temperature to allow them to warm up a bit and the yolks to settle. Mark an X or number on one side of each egg with a pencil. This will serve as your guide when turning the eggs (if your incubator has an auto turner, you can skip this step). Place the eggs in the incubator with the pointy end angled down.
Set your incubator in a quiet location out of direct sunlight where it won’t be bothered by children or pets. I like to put a piece of rubber shelf liner on the floor of the incubator. This helps the eggs stay in place as you turn them and also gives the newly hatched ducklings a textured surface to grip onto so they don’t slip.
Managing temperature and humidity. Duck eggs should be incubated at a temperature between 99.3° and 99.6°F (but again, check the setting for your particular model) for 28 days. The humidity level in the incubator is extremely important as well and needs to be monitored. Depending on the type of incubator you are using, the humidity can be controlled by filling small water reservoirs, or wetting a clean kitchen sponge and setting it inside the incubator. Humidity should be checked using a hygrometer, available from your feed store or online, if your incubator doesn’t come equipped with one, and kept constant according to your incubator instruction manual.
Marking the eggs with a pencil serves as a guide for turning them.
Moisture is lost through the pores in the eggshell, and air is drawn in. The air sac in the egg gets larger as an egg ages, whether the egg is being incubated or not. It’s crucial the air sac be the correct size in a developing egg to allow the embryo room to grow and air to breathe before it hatches. If the humidity is too high in the incubator, the air sac will be too small and the duckling can be too large and have trouble breathing and breaking out of the shell. Conversely, low humidity will result in a larger air space, a smaller, weaker duckling and hatching problems.
Weighing. Weighing each egg throughout the incubation process is the most accurate way to achieve the proper humidity levels for a successful hatch. Optimally, you want each egg to lose 13% of its weight from hatch to day 25 of the incubation period. More detailed explanations of relative humidity and egg weight loss is beyond the scope of this book, but the specifics can be found both on the Brinsea website at www.brinsea.com and Metzer Farms at www.metzerfarms.com.
Turning. If you are manually turning your eggs, you want to turn them a minimum of five times a day (even more is better, especially the first week) and always an odd number of times – turning 180 degrees side to side each time – so the egg spends every other night on the opposite side. This prevents the developing embryo from sticking to the shell and membrane. Embryos float and rise to the top each time the egg is turned. I set the alarm on my cell phone to remind me to turn the eggs at 6 a.m., 10 a.m., 2 p.m., 6 p.m. and 10 p.m. That schedule works for me; you can set one that works for you, or set the auto turner if your incubator has one. I prefer to turn the eggs manually. I like to think it allows me to bond with the growing embryos and feel more involved in the incubation process, but more likely it’s because I’m a bit of a control freak!
Utilize an incubator to maintain a constant temperature and humidity levels for your eggs.
Clean hands! It’s very important to wash your hands both prior to and after handling the eggs. Eggshells are extremely porous and bacteria are easily transmitted from your hands through the pores to the developing embryo. If during a candling you see a reddish ring inside the egg, that “blood ring” indicates bacteria have gotten inside the egg and it should be discarded. Contaminated eggs can explode and contaminate other eggs.
Day 5. Five days into the incubation, you should be able to see some “spider” veining when you candle the eggs. The air sac at the blunt end of each egg should have started to expand as well. Being careful not to drop the eggs, work quickly and don’t leave the light against the shell for too long because even a few minutes at temperatures above 100°F can kill the embryo. By day 5, the digestive tract, nervous and circulatory systems have formed and the eyes, ears and brain have begun to form. The heart is beating and the legs and tail have begun to develop.
Day 10. By day 10, candling will show significant expansion of the air sac in the blunt end of the egg and a developing embryo. The legs, toes and foot webbing, wings and beak will have begun to form and the bones are beginning to harden. The reproductive system is forming and feathers are beginning to grow. The egg tooth, a nub at the tip of the upper bill which helps the duckling crack the shell and hatch, is beginning to grow. Any eggs not showing any development by day 10 can usually be safely removed as they are most likely infertile or otherwise not going to hatch.
Starting on day 10, the eggs will benefit from daily misting and cooling. Once a day, remove the lid of the incubator and leave it off for 30-60 minutes. The eggs should be let to cool to about 86°F, so they feel neither warm nor cold to the touch. Then mist each egg with a spray bottle of lukewarm water and replace the incubator lid. This mimics a mother duck leaving the nest each day to find something to eat and maybe take a short swim, returning wet to her nest. The misting helps keep the humidity levels high and the membrane moist, which assists the duckling in hatching. The misting also cools the egg surface temperature slightly as the water evaporates. Studies have shown this can greatly improve hatch rates.
Day 26. Continue turning, cooling and misting the eggs as described until day 26. Day 26 is lockdown. At that point, one last candling should be done and any
