Incubation
Ordinary hens are used commonly to incubate guinea eggs, but guinea hens, turkey hens, and incubators also can be employed successfully. The usual sitting for a guinea hen is about 14 eggs, for a hen of one of the general-purpose breeds such as a Plymouth Rock, 18 eggs, and for a turkey hen, about 24 eggs. The incubation period for guinea eggs is 28 days, although frequently they start hatching on the twenty-sixth day and are all hatched by the end of the twenty-seventh day.
If the nest in which the guinea hen becomes broody is safe from any disturbance, she may be trusted with a sitting of eggs and more than likely will hatch out every egg that is fertile, provided all hatch at about the same time. As soon as the guinea chicks begin to leave the nest the hen will leave with them, and any eggs that are late in hatching are ruined unless they are placed in an incubator or under a broody hen before they become chilled. Guinea hens usually are too wild to be set anywhere except in the nest where they have become broody, and often such a nest is unsafe. Because of these disadvantages and the fact that guinea hens do not make the most satisfactory mothers for guinea chicks, ordinary hens are most often used to do both the incubating and the brooding, at least until late in the summer, when the guinea hens often are allowed to sit and raise a brood without much attention being given them. Broody turkey hens, when not needed to incubate turkey eggs, often receive a sitting of guinea eggs, and they hatch them quite as well as ordinary hens and also are able to cover more eggs.