One of the common ambiguities among bird breeders is how to determine when their bird lays an egg, whether that egg is fertilized or not. In this article, we intend to answer this question and provide a method for identifying fertilized bird eggs.
Fertilized or Infertile Egg?
To know if your bird’s egg is fertilized, you must first consider the living conditions of the birds. If a bird lives alone and does not have a mate, its eggs are definitely infertile. The eggs produced in this situation are merely laid during the mating season and do not have the potential to develop into chicks. 
However, when birds are kept in pairs and mating is observed, the probability of the eggs being fertilized is very high, unless in specific situations, such as poor sperm quality in the male, which causes the eggs to be infertile.
How to Determine if an Egg is Fertilized?
To check the fertility of the eggs, a penlight can be used. This method is facilitated by light. For this purpose, you need a light source. You can use a phone flashlight or a glow pen.
First, turn on the flashlight and shine its light on the egg. In this method, if the egg is fertilized, blood spots or the embryo inside the egg will be visible. If you see these spots, the egg is fertilized and can be placed under the bird or in an incubator. However, if no embryo or blood spots are observed, this egg is infertile. 
What is the Dark or Black Part Inside the Bird Egg?
You may have noticed a dark or black part inside the egg. This part is actually the contents of the egg, which includes the yolk and the egg white. These contents naturally lose their water over time and become denser. In fact, this part may become a contaminated and infected environment that can harm the egg and even the bird. Therefore, if your egg has these conditions, it is better to remove it from the nest so that the bird doesn’t waste energy sitting on it.
Important Points About Keeping Infertile Eggs in the Bird’s Cage
Infertile eggs hold no benefit for the bird. If these eggs remain in the nest, in addition to the bird wasting its energy sitting on the useless egg, they may lead to health and infection problems. Infertile eggs may rot over time, and this decay can pose risks to the bird and even to other eggs. Additionally, the presence of infertile eggs in the nest can cause weight loss and general weakness in the bird. 
Conclusion
Determining whether a bird’s egg is fertilized or infertile is a very important issue that can greatly affect the health and growth of the birds. Using simple tools like a flashlight, you can easily distinguish fertilized eggs from infertile ones and prevent health issues and energy wastage for the bird.
If you have difficulty in determining the fertility of bird eggs and wish to receive expert advice, bring the bird egg to the veterinary hospital for further examination so that our colleagues can conduct the necessary checks. 
Frequently Asked Questions
Are the eggs of birds that are kept alone fertilized? No, the eggs of birds that are kept alone are infertile because mating does not occur. How can we determine if a bird’s egg is fertilized? To determine the fertility of a bird’s egg, you can use a penlight or a phone flashlight. Simply shine the light on the egg. If blood spots or an embryo are present, the egg is fertilized. Why should infertile eggs be removed from the bird’s nest? Infertile eggs can cause infection and contamination in the nest and waste the bird’s energy for sitting on them. They may also lead to weakness and weight loss in the bird.
