There is no definite answer to an unborn chick's gender, even if you candle the egg. Some breeds, you can't even tell until it lays an egg.
When the egg is really hard, you know that Its been in there for a long period of time and, that its kindof heavy.
There will be kind of pocket in the egg which contains enough oxygen for the chick to breathe in the egg for 21 days.
It is the yolk that provides the nutrients for an unhatched chick.
They keep the egg cratled in the father's feet
The chick grows in the albumen (the white of the egg) and feeds off the yolk.
The egg yolk nourishes the chick until it hatches.
The developing chick feeds on the yolk sac, much like the baby of live bearing animals attaches to the placenta. The chick has enough nutrients when born to got 24 hours without beginning on chick starter.
A young chick develops inside the egg and can be hatched naturally or through hatcheries. The young chick depends on the egg yolk for nutrients.
The chick egg has much more yolk than the frog egg. A blastopore in frog egg and a premitive groove in chick egg both have the same basic function which is to mark the origin of gastrulation
When the chicken haches.You can't tell if the chick is growing by just whatching.To see if the egg is growing,hold it up to a bright light.If the egg is fertile,it will have a dark spot in the center indicating that tha chick is growing.If the egg is infertile,it will be somewhat clear(eat it).This practice is called candling.
The yolk of the egg is food stored for the chick during its growth.