Hi Darwin,
It sounds like your chicks are starting to pip! Continue to be patient and allow the parents privacy – don’t check on the eggs too much because this is a sensitive time. It takes time for each chick to break out of the shell, so try not to worry or interfere. Once they start, it can take up to 48 hours. Each chick will work for a while and then rest. They have a yolk sac so they are still getting nutrients during this process. Each egg was laid with a day in between, so the chicks will hatch at different times, too, depending on when the parents began sitting on the eggs. Hopefully all goes well. If it takes too long, the chick can start to get too dry, but it is very risky to try to assist a hatch, so it’s best to hope they each get out on their own. You can search for assisted hatch for a cockatiel and watch some videos. But again, only do this as a last resort. Once hatched, each chick is likely to rest on its back for a while. They still have some egg sac to absorb so it’s OK if the parents do not feed it for a few hours.
I hope the male’s leg has been treated and is better. Make sure the parents have some egg food – cooked eggs with the shell washed, crushed and cooked with the eggs.
Thanks for the update & best of luck!
Brenda