Headaches caused by hormonal problems due to changes in hormones are usually experienced in one side of the head. Headaches in the back of the head are normally due to mental tension, stress, improper posture, and depression. It is mostly the kind of pain that is sharp in the head that comes and goes.
If for some reason the temperature has dropped below the correct temperature on a few occasions, you could find some of your eggs only hatching on day 22, 23, or even on day 24 or 25. Whereas fertilized chicken eggs usually take exactly 21 days to hatch, most duck eggs take 28 days, apart from Muscovy ducks.As a general rule of thumb, the eggs of Muscovy ducks take 35 days, but once again, it can vary slightly depending on conditions.andling fertile chicken eggs during incubation. Once fertilized chicken eggs have been under a brooding hen or in an incubator for a period of about three or four days, you can candle the eggs to see if they've started developing.
6. Record the day and how many eggs you've incubated on a calendar. You should be able to estimate your hatch date based on average incubation times for the bird species you want to hatch. For example, chicken eggs typically take 21 days to hatch, whereas many duck varieties and peafowl may take 28 days.andle the eggs after 7 to 10 days. Candling the eggs is when you use a light source to view how much space the embryo occupies within an egg. After 7 to 10 days, you should see development of the embryo.