The eggs take approximately 30-45 days to hatch from the date of the last egg being laid. Since we do not know how many eggs were laid, we cannot ascertain how many will hatch. However, it is a rarity to have all eggs hatch. Usually, there will be eggs that are either infertile or something goes wrong and the cygnet dies in the egg prior to hatching. Predation can also be a factor in the number of viable offspring produced. The Regal Swan