Breeder pairs of parrots often lay infertile clutches, so it makes sense to candle the eggs before they hatch to determine if they are fertile or not. Infertile eggs may be removed from the nest to encourage the pair to try again, and arrangements may need to be made to care for the babies if the eggs are fertile. Candling eggs for fertility is quite simple, and problems such as hairline cracks can be detected during the candling process as well.
Things You'll Need
- Clean sand or finch seed
- Candling light or bright LED flashlight
Wait until 14 days have passed from the time the last egg was laid before candling eggs for fertility. There are two reasons for this; the vascular system will be well-developed and easy to see after 14 days, and the embryo is less likely to be disrupted by being moved at this point.
Use caution when removing the eggs from the nest box for candling. Tap the side of the box to encourage the parrot to leave the box. If the parent birds will not leave the box, it is best to wait until they come out on their own.
Carefully transport the eggs to a darkened room. Placing the eggs in a bowl of clean sand or finch seed will help prevent them from rolling around and being damaged while you are carrying them.
Position the egg and the candling light, or LED flashlight, in such a way that the light shines through the egg. You should be able to visualize the contents of the egg quite easily. If you cannot, then reposition the light and/or the egg until you can clearly see the air cell.
Examine the egg closely. At this stage in development, you should be able to see the vascular system within the egg. It will appear as a "spiderweb" of red blood vessels on the inner surface of the egg's shell. If the egg is infertile, you should be able to see a round, yellow yolk inside. A dark area, rather than a yolk, usually indicates a dead-in-shell embryo. Any hairline cracks should also be visible, and if the egg is fertile, these should be repaired by applying a thin coat of Elmer's glue.
Return the eggs to the nest, or artificially incubate, if they are fertile. In general, it is best to return infertile eggs to the nest as well to prevent calcium depletion from repeated laying in the hen. Dead-in-shell eggs should be sent to a laboratory for testing or discarded. They will decompose if placed back in the nest, potentially causing health problems for the other eggs.
Tips & Warnings
- Black patches around cracked portions of an egg indicate fungal infection, usually mold. These eggs are not viable and should be discarded.
- If an egg appears infertile, you may want to attempt artificial incubation. Sometimes eggs that are not being properly cared for by the hen will not develop, and thus appear infertile.
- Use extreme caution if you must remove eggs from a nest box while the hen is inside. Damage to the eggs or your fingers may result.
- Avoid using incandescent flashlights to candle eggs. The heat from the light could injure the developing embryo.
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