Proper Egg Temperatures

• Eggs require a temperature range of 99 to 102 degrees Fahrenheit to hatch. In addition, the relative humidity that the eggs are in or the moisture level in the air needs to be 50 to 55 percent for the first 18 days and 65 percent during the last three days of incubation.
  
  

Coldest Surviving Temperature

• The lowest temperature an egg can be in and still hatch is 50 degrees Fahrenheit. The fertilized egg can survive for up to 10 weeks in 50-degrees Fahrenheit temperatures as long as they are stored with the large ends up. If you are storing them for longer than two days, you need to gently turn the eggs to prevent the yolk from sticking to the inside of the eggshell.
  
  

Incubating Eggs

• Chicken eggs should be incubated as soon as possible once they are fertilized. Incubators can be purchased on-line or at local farmer supply stores. They heat and humidify the air the same way a mother or broody hen does to prevent the embryos from drying out and to keep them warm so that they can grow.
  
  

Fertilized Eggs

• Not all of the eggs that your hen laid will be fertilized. Often only between 50 and 75 percent of the eggs will hatch. After three days of incubating, hold a white-shelled egg in front of a candle or a lit light bulb with a box with a small hole in it for the light to shine through. Hold the egg in front of the light, and look for a cloudy spot or a mass in the egg, which is the growing embryo. If you don't see a spot or mass, the egg may be infertile. At seven days old, eggs that appear clear when candled are infertile eggs that were either never fertilized or the embryo did not survive.