Hi Emma,
Unfortunately no, this isn’t going to work. You will just end up with 4 rotten eggs. Cockatiels eggs are hard to incubate. The temperature and humidity have to be right and the eggs have to be turned day and night. Then even if the eggs do hatch, cockatiel chicks are almost impossible to keep alive if you try to hand feed them from day 1. Even the most experienced hand feeders will lose most day 1 cockatiel chicks. They seem to do well for a few days and then they die. They need what they get from their parents for the first 2 weeks in order to thrive and grow.
A first time pair almost always messes up their first clutch. Often the eggs aren’t fertile, or they get broken, the parents don’t sit on them or they don’t feed the chicks. When you breed birds, you have to be prepared for clutches to fail. It is going to happen, even with pairs that normally produce well. Sometimes things just don’t work out. If this is too hard for you to handle, then don’t let the pair breed again. I would replace these eggs in the nest box and give the parents a chance to sit on them. They need to learn, and by taking the eggs away, they have no chance to learn, so the eggs have no chance. It’s true they probably won’t hatch, but they may not even be fertile. Regardless it is a learning experience for the parents. And the eggs have no chance with your plan, I’m sorry to say. Whether you return the eggs or not, once they are done with this clutch, you need to remove the nest box and rest the pair for 6 months, and then either let them try again, or do not return the box and don’t breed them again. They will probably fail at least once more, but again, they will hopefully learn and later on finally raise some chicks.
Thank you for Asking Lafeber,
Brenda