In order to use the natural method to hatch and raise chicks, you must have a broody hen (one ready to set). This is genetic, as broodiness has been largely breed out of most production strains. The Mediterranean class are also not noted for their broodiness. Most Heavy Breed of hens will go broody as will most bantams.
You can not make a hen go broody. There is no special feed or hormones that you can give. Even praying to "The Great Chicken in The Sky" will not get a hen to set. Broodiness is part of the early molt process. A hen will loose the feathers on her breast. The eggs are warmed by the skin of her breast, not by her feathers. Her body temperature also has to drop to about 100 degrees F. Her metabolism has to drop. She will only get off the nest once a day, for about 1/2 hour to 1 hour. This is the time she will eat, drink, and poop. You can tell when you have a setting hen as not only will you see an extra large amount of feces, it will have an odor that will "knock your socks off" when she first defecates. She will be that ball of feathers that is running around in the yard clucking to her self, trying to stay away from the other chickens. They will hassle her if they have a chance. When on the nest she is the hen that will "growl" at you and the other hens when they come near the nest. Some will even pick at you. Most hens will set during the spring, when the number of hours of daylight is on the increase.
Having decided to use the natural method of hatching and rearing chicks, you must be prepared. A hen will set when she wants to, not when it is convenient for you. Depending on the number of hens you plan on setting, you will need nest boxes for them all. Small cardboard boxes, the size to fit the breed, work well. They can be burnt after the chicks hatch, controlling illness.
Once a hen has the desire to set, she will. Several days before she is ready, she can be heard clucking to herself as she moves around. If she is in a cage mark down the cage number. If she is in a flock mark down her leg band number. When you do chores if she is on the nest, take her out and set her on the floor. Don't take the egg(s). Check back at dusk, if she went back in the nest, chances are that she is ready.
If your breeders are set up in pairs, the hen can set, hatch and raise her chicks in her cage. Cut the flaps off the box, place some fresh wood shavings in the bottom of the box. After placing enough eggs to fill the nest, but not more than she can cover (11 works out well) place the hen in the box at dusk. She can come and go out of the nest as she pleases to eat, exercise, and get rid of waste.
For a hen in a flock, her nest box is set up differently. On 2 sides of her box air vents are cut. They should be about 1 inch wide, an inch from the top and ends. Leave the flaps on so that the box top can be closed. With fresh shavings in the box, place her and the eggs that she is on in it. She may be able to cover more eggs than she is on. From the eggs that you have been holding back, take enough to fill her nest, but no more than she can cover ( 11 works out well ). Close the box and set it somewhere safe and quiet. This way the other hens in the pen will not be able to pester her and drive her out of the nest. She will need to be taken out of her box for around 1/2 hour each day to eat, exercise and get rid of waste.
A hen in a cage can raise her young in her cage, until they start to become crowded. For a hen from a flock, she should be given a cage or large box for a few weeks or until the chicks start to feather. At this time she can be returned to the flock with her chicks, but watch them to be sure that the other hens do not pester the chicks too much. Once the other hens get use to chicks running around, they hardly pay any attention to them.
Althrough the laying hens in a flock rarely pester the chicks when interduced to the flock, this is not the case with broodies. Not only will 2 hens with chicks fight, they will pick at and even kill chicks that don't match their brood as to color and size. Therefore do not house 2 hens with chicks in the area/house/cage. There is less of a problem with free range hens as the hens and chicks can get away. But then there is the preditor problem.
Hatching and raising chicks the natural method is harder and requires more work and time than hatching in an incubator and raising in a brooder. However the reward of seeing a chicken family far out weights the time and work required.