An internal-combustion engine needs four things to run. They need fuel, mixed with air, in a ratio of 14.7 to one. An ignition-spark lights the fuel and air mixture, creating combustion. Compression of the fuel and air mixture makes it explosive. The final necessity is proper timing, of the components.
1 The length of time it takes for eggs to hatch after incubation begins depends on the species and temperatures. 2  For bluebirds, it USUALLY takes about 12-14 days from the date the last egg was laid.3  Different species have different incubation periods, which can vary within a species due to temperature inside the nestbox. Depending on when incubation begins (on the last, or next to last egg), eggs in the same nest can hatch a day or several days apart. 2  It also takes a while for the bird to break through the shell. 3  It could be a new egg from a subsequent nesting if you didn't clean the box out immediately after the last fledging.
Store eggs up to seven days prior to placing them in the incubator. Store the eggs at 55 degrees and 75 percent relative humidity. Store the eggs with the small end pointed down. Turn the eggs at least once a day. To easily turn eggs, place a 6-inch block of wood under one end of the carton to make a 45-degree angle. The next day place the block under the other end of the carton. Allow eggs to warm to room temperature four to eight hours prior to placing them in the incubator.