Two things with your calendar.
Sex of the chick is determined by the hen when she gives the developing egg her Chromosomes. Sex is determined before the egg is even fertilized. I'm not sure where you got that about the sex being determined on Day 5, the 9th on your calendar. Perhaps that is when an expert may be able to tell whether it will be a boy or a girl, but the sex was determined long before.
Don't count on the eggs hatching exactly on Day 21, which is correctly shown as the 25th on your calendar. For various reasons it is not that unusual for eggs to hatch more than a full day early or late. That 21 day thing is more of a target than a law of nature. Even under a broody hen I often have eggs hatch a couple of days early. So don't be concerned if you see a hatch a day or even two early. Don't give up hope if they are a bit late.
Lockdown is correct also. You got that right.
Sex of the chick is determined by the hen when she gives the developing egg her Chromosomes. Sex is determined before the egg is even fertilized. I'm not sure where you got that about the sex being determined on Day 5, the 9th on your calendar. Perhaps that is when an expert may be able to tell whether it will be a boy or a girl, but the sex was determined long before.
Don't count on the eggs hatching exactly on Day 21, which is correctly shown as the 25th on your calendar. For various reasons it is not that unusual for eggs to hatch more than a full day early or late. That 21 day thing is more of a target than a law of nature. Even under a broody hen I often have eggs hatch a couple of days early. So don't be concerned if you see a hatch a day or even two early. Don't give up hope if they are a bit late.
Lockdown is correct also. You got that right.