Chicken eggs purchased from a grocery store cannot be used as hatching eggs because they are not fertile. Fertile eggs are obtained from sources that have roosters in their flock. Hatching eggs need to be incubated within 7-10 days after being laid as hatch-ability significantly decreases after 10 days.
Until they are incubated, hatching eggs should be stored in cartons or cases, large end up, at 50 to 60° F. with a relative humidity of about 75 percent. If the hatching eggs are to be stored for more than 2 to 3 days before they are incubated, their positions should be changed each day to reduce the tendency for the yolks to stick to the shells.
After you purchase your eggs, please follow the directions that come with your incubator for best results.
Once your chicks hatch, go here and follow the directions for starting with baby chicks.
Hatching eggs in an incubator is more involved as it requires more equipment and takes considerably more time and attention. The approximate incubation period of a chicken is 21 days and eggs need to be turned at least 3 times a day unless you have an automatic egg turner. Temperatures in the incubator must be closely monitored as well. Most quality incubators will have a thermostat controlled heat source.
If you decide to start your flock with hatching eggs, you can expect to pay around $5 for a dozen eggs of a common breed of chicken. If you want to purchase hatching eggs from a more exotic breed, you can spend up to $5 per egg. Hatching eggs can be purchased on eBay or from a chicken hatchery.
Incubators start out at about $50 for the basic model that holds 6 eggs and go as high as $1500 for a more advanced high capacity model with automatic turners, temperature and humidity controls. An egg incubator that holds about 4 dozen eggs with automatic turner and thermostat controlled heater will run about $175 - $500.
As with anything, the more expensive incubator models will have more features, be a little easier to use and in general, give more positive results.