Hi Emma,
Unfortunately that is not going to work. Cockatiel eggs are very hard to incubate. The temperature and humidity have to be just right, and you have to turn the eggs often, 24 hours a day. If everything isn’t perfect, the chicks won’t develop or they won’t develop properly and often diet within hours of hatching. A heating pad will not do anything but cause the eggs to rot very quickly. It’s best to leave the eggs with the hen and let her learn. If you take them away, she will never learn. If these eggs do not hatch, then remove the nest box and rest the pair from breeding for 6 months. Then you can return the nest box and let them try again. The nest box must be removed after each clutch of eggs and the pair rested for 6 months. If the hen still does not care for the eggs by the 3rd try, then you shouldn’t breed this pair again. Some birds just never make good breeders or parents.
Thank you for asking Lafeber,
Brenda