First to start incubating you must have a rooster in order for the eggs to be fertile , then gather some eggs , you can store eggs at 55 degrees for up to ten days in order to set all the eggs at the same time and so all eggs hatch around the same time, if you put eggs under a hen at different times all the eggs might not get incubated long enough to hatch, above is whats called natural incubation this is a brooding black Austrolorp.
Hatching eggs in an incubator is called artificial incubation, it takes 21 days for a chick to hatch, on the 20th day the chick gets so squished that it breaks a little hole in the egg where it gets its first breath of air then rests for 3 to 8 hours then chips around the shell then pops out exhausted.
Above is two chicks that hatched early , chicks also need special feed such as chick starter because foods such as lay ration have extra calcium that can seriously damage their kidneys.
This is a Black Mottled d'uccle that hatched on time.
This is the early Porcelain chick from above.
This is the same chick from above at about 2 months old, below is his dad at the same age, chicks get fully feathered at 4-6 weeks cockerels learn to crow at 6-8 weeks and pullets start laying at20-24 weeks.
This is Platinum at 2-3 months old compare to how much he looks like his son,