Q: My son got up this morning & noticed that our tiel had laid an egg. The egg was on the bottom of the cage and there was a little dent or bump on it. I was wondering if we should keep it and hope for the best or throw it out?

The male is sitting on the egg more than she is, and I don't know if that means that the egg is OK or not. How long does it take before you can tell if it's a good egg?

Linda S. Rubin explains:

Without actually seeing the egg, I can only venture a guess, but it sounds as though the egg is damaged and unlikely to hatch. This is also probably the reason why you found it on the cage floor. Cockatiels instinctively act to remove any “worthless” eggs and lay another to replace the one they lost. This is nature’s way of preserving the gene pool by increasing the odds of survival of the offspring when eggs are lost due to predation or accident.

It is common for inexperienced cockatiel pairs to fail to sit eggs tightly. Cockatiels are very sensitive to noise. They frighten easily, which can lead to damaged eggs when they panic and jump up and down. An old trick of budgie breeders was to paint a hairline fracture with clear nail polish, allowing it to dry before replacing the egg. This worked once for me, however, it all depends upon the extent of the damage. The risk of frightening the pair further when eggs are returned to the nest must also be weighed.

Male cockatiels share in incubation duties, sitting eggs in the morning and into the early afternoon until the female returns. Many cockatiels will not sit the  full time until the second or third egg appears. Inexperienced pairs might have several “practice nests” before they become successful at incubating eggs full time.

Candle eggs by the fifth day when they show the first signs of fertility, which will appear as a red spot with wavy lines resembling a spider, which is the heart pumping blood through the veins.

Never remove cockatiel eggs unless damaged, or broken, because the female will always lay additional eggs to make up for the loss and frequent removal of eggs can trigger excessive egg-laying. Allow birds to choose when to abandon their eggs.

Because egg-laying is a drain on the female’s calcium reserves, offer a fresh supply of cuttlebone, which provides the necessary calcium to form the outer egg shell. Without adequate calcium, soft-shelled eggs, osteoporosis (making birds vulnerable to multiple fractures and broken bones), or life-threatening peritonitis can result.