I have a pair of cockateils they have had there eggs for around a 16 days or so well they have been incubating them for that much time. the cockatiels use to take turns incubating the eggs and more commonly were both inside the nest box. lately they have both been in the box for 4 days now without leaving. does this mean they are about to have the babies or are they already born. they have at least for eggs so i know they are incubating already.

Usually a fertile egg will hatch anywhere from 16-23 days after the birds start to sit on them( incubate) the egg. If the egg is fertile you will see a very white egg, if it's got a yellow look to it or beige it is more than likely not fertile. Now to the point of the egg hatching. If you have very keen hearing you can actually hear the baby start to peep on or about the 18th, day and if you don't hear anything another way of being able to tell is to wash your hands very well and check the egg for a little pip mark near the end , that would be where the baby is tapping on the egg trying to pip it's way out.You will be able to gear the baby peeping though if you are in a nice quiet environment and it's the most beautiful experience in the world.