Getting started: (fixed variables)

BUILDING THE INCUBATOR AND RUNNING IT
In order to hatch eggs the first thing you need to do is build an incubator.  It is simple and easy to do using a cardboard box and a light bulb, so there is no need to purchase one.  This box will be the embryos "home" for the 21 day incubation period.
In order to have success with hatching you must achieve a constant temperature of 38.6˚ C (101.5˚ F) along with the correct humidity and ventilation.

Materials needed for incubator:

Preparing the box:

Tape closed the bottom flaps of box and make sure flaps abut each other when they are closed.  Cut off top flaps but leave about a 2.5cm lip to hold the Plexiglas top in place.  Use the cardboard scraps to reinforce sides of box and add to its insulation.  Strategically wrap box with masking tape or duct tape to provide extras stability as needed.

Install heat source:

Attach the electrical utility box to the side of the cardboard box and pull wires from chord through the side.  Attach the two bare ends of the chord to the porcelain light fixture.  Make sure to use porcelain for safety!  Attach the fixture to the utility box using ¼ - 20 nuts and bolts and use washers for reinforcement.  Screw in a 60 watt light bulb, and if 60 watts does not warm the box sufficiently, you can use a higher wattage bulb.  To slightly increase temperature you can place aluminum foil on top of the Plexiglas lid to reflect back the light and heat.

Ventilation and Humidity:

If embryos do not get adequate ventilation they will suffocate and die.  The embryo is living tissue and needs to exchange oxygen and carbon dioxide through its pores throughout the growth process.  The hard shell is a protective covering made of calcium carbonate and contains about 7,000 pores that allow the transfer of gases.  The still-air incubator needs vents in the sides to provide air circulation within the incubator.  To ventilate the box simply cut in 5-7cm flaps towards the bottom of the sides and back of box.  Only cut the vents on three sides so that they can be opened and closed as needed for adequate cross-ventilation.  You will also need to cut a small vent toward the top on each side to let out excessive heat.  A larger flap in the front needs to be cut big enough so that you can get your hand comfortably through the door and turn the eggs and add water to the pan as needed.  The pan of water needs to be placed at the bottom of the box and a screen that fits snugly will sit on top of the pan.  The water in the pan will slowly evaporate and provide humidity to the eggs.  Proper humidity is important because it affects the weight of the embryos and keeps the eggs from losing too much or too little moisture during the incubation process.  Place the box on a sturdy table away from any drafts and then fill the pan with tepid water.  If the pan is left to dry out the embryos will also shrivel and dry out.

Top "window" of incubator:

Rest the Plexiglas on the lip of the box and use masking tape or duct tape to secure it in place.  This creates a window and allows a view of hatching without disturbing the chicks.  Place the meat thermometers on either side of box approximately 3 cm above where the eggs will be laying on the screen.  Plug in the chord and begin recording temperatures inside the box.  Adjust vents and bulb wattage as needed to obtain the ideal temperature of 38.6 degrees Celsius (101.5 degrees F).  Maintaining this temperature without fluctuation is the most important part of successful hatching.

Adjusting temperature:

Begin running the incubator at least one week prior to getting eggs to ensure that the temperature will remain constant.  Record temperature at various times of the day, every day, and adjust vents and bulb wattage until incubator remains at 38.6 degrees Celsius for several days.  After making adjustments to vents or bulbs wait for hear to adjust before taking temperature readings.