For breeding, we rely on natural incubation. This limits the number of offspring, of course, a lot. It is only possible to keep 2 max. 3 hens together with one rooster, otherwise there is to much interfere between the hens so that a natural incubation is impossible. In addition you have then only on clutch of eggs per hen, which is only 5-6 eggs per year.
However, this is a must in our view, when we talk about conservation breeding, because only with this it is possible to conserve reliable the natural breeding instinct of the hens.
Another advantage of the natural incubation is, the chicks are growing better and there is no faulty imprinting on humans, which can lead in aggressive animals.