Things You'll Need
- Egg incubator
- Flashlight
Instructions
Set an egg incubator to 99.5 degrees Fahrenheit with a relative humidity of 55 percent. This translates to a temperature of 84.5 degrees on a wet bulb thermometer.
Place the eggs in the incubator with the small side down. Discard eggs if they are cracked, dirty, oversized or undersized. These types of eggs typically do not hatch well.
Rotate the eggs at least four times per day. Some incubators come with automatic turning devices that you can set to rotate the eggs at an interval of your choosing. Check the temperature of the incubator when you rotate the eggs to make sure the incubator is working properly and the temperature is staying consistent.
Check the eggs about a week after you place them in the incubator. Look at the embryo inside by making a wide circle with your fingers and thumb and resting the egg on top. Shine a high-powered flashlight under your fingers so the light shines through the egg. Discard any eggs that are clear or cloudy.
Increase the humidity in the incubator as the eggs get ready to hatch. Mallard duck eggs typically hatch between 23 and 30 days after they are laid, though you may just have to look for signs of hatching, such as vibration or movement in the eggs if you do not know when they were laid. Increase the humidity to 65 percent a few days before hatching and up to 80 percent as the hatching process begins. Lower the humidity back to about 70 percent once the eggs are nearly done hatching.