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You can build your own incubator, or you can buy one from a farm supply company. If you are buying one, make sure that it has easy to control temperature and humidity, as well as good egg-turning options. One of the biggest factors when choosing an incubator is the number of eggs you intend to hatch. Usually only about 50-70% of the eggs that you incubate will hatch, and then half of those will turn into roosters. A stable room temperature will allow the incubator to keep a stable internal temperature much easier. Avoid placing the incubator next to a heater, or next to a window or door. You will need to check your incubator often, so make sure that you can access it easily. If you didn’t mark your eggs when you collected them, you should mark them before putting them in the incubator. This will help you know if the egg has been turned or not. Allow the incubator to run for a few hours before placing the eggs in. This will allow the incubator to reach the heat and humidity it needs. If your incubator has fans it should maintain a constant temperature of 100 °F (38 °C). If it does not have fans, keep the temperature at 102 °F (39 °C). Humidity for the first 18 days should be around 40%. Eggs should always have the large end facing up, or be lying horizontally with the large end tilted up. The small end should never be facing up, or the eggs will not develop properly and chick will most likely die trying to hatch. Eggs need to be turned around 5 times per day. Turn the eggs gently to avoid damaging the embryo. Do not turn the egg in the same direction each time. They do not get turned on the last 3 days before hatching. Candling eggs allows you to tell if embryos are actually growing inside or not. You will need a bright flashlight and a dark room to candle the eggs. Hold the egg with the large side upwards, and shine the flashlight through it. You should be able to see blood vessels beginning to develop, as well as the air sac on the top.  You should be able to start seeing blood vessels after a few days of incubation. You should see a developed embryo after about 7 days. Throw away any undeveloped eggs between days 10 and 14. Humidity needs to be increased to 60-70% the last 3 days to prevent membranes from drying out. Do not open the incubator in the last 3 days. The hatching process can take the better part of a day. As soon as you notice pipping, increase the amount of oxygen that is entering the incubator by opening vents. The newly hatched chicks will not need to eat or drink for 48-72 hours, so allow the incubator to keep working as later chicks hatch. Avoid helping the chicks hatch. Chicks that cannot hatch on their own will most likely not survive into adulthood. One the hatching process is complete and the chicks are dry, you can transfer the chicks to a brooder where they will be raised. You can either build your own brooder or purchase one from a farm supply store.  A 40-watt bulb in a bedside lamp makes for a good source of heat. Use a red bulb to hide injuries so that the other chicks will not pester an injured one. The chicks need a temperature of 99 degrees F the 1st week, dropped by 5° each week until brooder temp is equal to outside temp or chicks are fully feathered.   Keep the box in an area that is as draft-free as possible, and use wire to prevent cats from gaining access. After about 6 weeks, the chickens will be ready to be introduced to your flock. Introduce them slowly, and ensure that everyone is getting along before moving them in permanently.

Summary:
Obtain an incubator. Set your incubator up in a temperature-controlled room. Mark your eggs if you haven’t already. Preheat your incubator. Place your eggs in the incubator. Turn the eggs. Candle your eggs. Allow the eggs to hatch. Move the chicks to a brooder. Introduce the chicks to the flock.