My cockatiel laid an egg?

I would go back to the pet store and tell the guy that sold you the Cockatiel that she is laying eggs and unless he can provide you with a male, he better take her back! The male is responsible for helping the female. He will feed her so she can incubate the eggs. That was completely wrong and irresponsible for someone that works at a pet store to do that for you! The eggs may not be fertile. Just leave them in there until about 4 days old and candle them. Hold the egg up to a flashlight and if you see yolk and reddish membranes, they are fertile and she will NEED a male! These pet stores selling females to people by saying oh she will lay eggs makes me sick! Someone such as yourself may think that is great and you will have baby Cockatiels, but it is so wrong and so far from the truth! Good Luck!