Expert Tips for Incubating Chicken Eggs

Enlarge Image Image Gallery A broody hen takes the work out of incubating eggs. She'll do it for you. iStockphoto.com/Borko Ciric

Which came first, the chicken or the egg? For most backyard poultry enthusiasts, the chicken came first – well, more correctly, the day-old chicks first arrived in the mail. But that’s not the only way to create your first flock or maintain your existing one. For folks who are uncertain about receiving live animals through the mail, or simply cannot handle the minimum number of day-old chicks that most hatcheries require, incubating fertile eggs is an attractive alternative. Likewise for folks who keep a rooster in their flock, incubating eggs is a great way to increase the flock size, or to provide replacements for birds that have been culled. Hatching fertile eggs need not be difficult, but your success rate can be increased by following a few guiding principles.  

Environmental impact 

Chicken eggs need a fairly specific environment to develop properly and hatch successfully. Perhaps the most important parameter is temperature – chicken eggs should be incubated at a temperature between 99 and 102 degrees Fahrenheit (99.5 is often considered to be ideal) and 50 to 65 percent relative humidity (60 percent is often considered the ideal). To facilitate proper aeration and gas exchange between the embryo inside the egg and the outside world, the eggs must not be held in a tightly sealed container.  

Chicken eggs typically hatch after 21 days of incubation. Consider that number to be a target – not an absolute. During the final three days of incubation, the eggs should ideally be located in a slightly cooler (98.5 degrees) and more humid (65 percent relative humidity or greater) environment to facilitate successful hatching. Lowering the temperature helps account for the extra heat that the larger embryos produce as a result of their metabolism, and the increased humidity helps keep the chicks from getting stuck to the membrane that’s located just inside the egg shell as they break out of the shell.  

Mindful manipulation 

Just as temperature and humidity are important to maximizing the hatch, eggs need to be moved around on a regular basis for best results. Changing an egg’s attitude helps exercise the embryo and prevent it from sticking to the shell. In general, eggs should be incubated with their pointed ends down (air cell up) – but it is also important to turn or tip the eggs back and forth at least twice a day – the more often they are turned, the better. During the hatching phase, it’s best to lay the eggs on their sides.