Poultry Judging Practice Test

By the 18th day of incubation, what percentage of egg weight should be lost?

1. 5%

2. 10%

3. 12%

4. 15%

The correct answer is: 12%

By the 18th day of incubation, a loss of about 12% of the egg's weight is considered optimal for proper development of the embryo. This weight loss is primarily due to the evaporation of moisture from the egg. Achieving the correct percentage of weight loss is crucial for ensuring that the developing chick has enough room to grow while also maintaining the necessary humidity levels inside the egg. If too much moisture is retained, the risk of malformation or improper development increases because the chick may not have adequate oxygen supply. Conversely, if too much weight is lost too quickly, it can lead to dehydration of the embryo, which is detrimental to its growth. Therefore, reaching that 12% mark by the 18th day allows for the right balance that supports the healthy development of the chick leading up to hatching.