Hi Manuela,
Did you mean to say she is sitting on the eggs or is she breaking the eggs and eating the inside? “Hatching” is what happens when a chick emerges from an egg. If she is eating the eggs, this is great because it replenishes the protein and calcium it takes for her to form the eggs. Without a male, the eggs are not fertile, but they will contain a yolk and liquid, just like chicken eggs from the grocery store. You can let her sit on the eggs if she wants to. She will most likely abandon them in 2-3 weeks. Do not give her a nest or anything she can use for a nest. You don’t want to encourage egg laying. Single Cockatiels will often lay eggs, but many of them will become chronic egg layers. If this happens, you need to take her to an Avian Vet for a hormone shot or implant. The best way to avoid this is to remove any hormone triggers. No nest, bird hut, tent, box or anything she can sit in. Do not give her anything she can shred like paper or cardboard. Limit her light to 8-10 hours by covering her cage early each evening. When you handle her, limit any petting to her head and neck. Rearrange her toys and move her cage to a different place in the room every week or so. If she chooses a corner in her cage to nest in, hang toys there to keep her from settling there. When she is out, don’t let her get in dark, cozy areas. While she is sitting on these eggs, do not make her more comfortable – clean her cage as usual and keep your regular routine. Hopefully she will get this out of her system and not lay eggs again right away.
Thank you for asking Lafeber,
Brenda