The incubation period for chicken eggs is approximately 21 days, although it can vary slightly depending on the breed of chicken and the temperature and humidity in the incubator. Here are the typical hatching days for chicken eggs:

• Day 1-7: During this time, the embryo is developing and growing rapidly, but it is difficult to see any changes from the outside of the egg.
• Day 7-14: By this time, you should be able to see some changes if you candle the eggs (hold a bright light up to the egg to see inside). You may be able to see veins, the embryo moving, and the formation of the beak and eyes.
• Day 14-18: The chick is now fully formed, and it will spend this time positioning itself for hatching. It will break through the air cell at the blunt end of the egg, and turn itself so that its head is pointed toward the air cell.
• Day 19-21: Hatching day! The chick will use its egg tooth (a small bump on the end of its beak) to crack the shell, and will gradually work its way out of the egg. This process can take several hours, and the chick will be wet and tired when it finally emerges. Give it time to rest and dry off before handling it.

Note that hatching can be a delicate process, and it’s important to provide the right conditions (temperature, humidity, and ventilation) for the eggs to develop properly. If you are new to hatching chicks, it may be helpful to consult a poultry expert or do some research to ensure that you are providing the best care for your eggs.