Chickens and eggs ...
In the diagram, you see the purple structure...that is the female reproductive tract: ovary, oviduct, (and uterus isn't labeled).
The yellow yolk of the eggs we eat is actually an "egg" ovulated from the hen's ovary...and it travels through the oviduct and uterus, gaining an egg white and a shell along the way; then out the cloaca, and in to the hen's nest.
A producing hen ovulates regularly, actually about 30 minutes after laying a finished egg. Hens of certain breeds
which are well cared for, will lay an egg nearly daily.
As it passes "down" the oviduct, the yolk rolls, and layers of albumen (egg white) are added around it. If the transit is more rapid than normal, layers of albumen will be fewer than normal, and the finished egg as we know it, with egg white and hard shell, will be smaller than normal. A laying chicken's oviduct is about two feet long! It generally has more than one
egg developing in it at a given time, each at a different stage (location) of development.
At the isthmus of the oviduct, lining cells produce a membrane which surrounds the yolk and egg white (you've seen that membrane when you've peeled a hard boiled egg).
Most of the passage time for the egg is spent in the "shell gland" (uterus) of the hen's reproductive tract... some twenty hours are needed to coat the yolk and white with the shell, made durable by minerals and oval shape.
When the egg is complete and ready to be laid, it is passed through the cloaca to the nest...and a neat thing is that the passage of the egg through the cloaca actually forces a physical barrier to cover over the intestinal entry to the cloaca...therefore, the egg shell stays clean.
The hen in the photo is a Rhode Island Red pullet. She is in a nest box, getting ready to lay her egg.
I looked up the derivation of the term "pullet". It is the English version of "polette" (young hen) or "poulet" (young chicken). Those words are from northern France. I guess you can imagine from where the word "poultry" is derived as well!
Pullets are young birds...from a few months of age through about one year of age. They lay a small to medium sized egg as compared to their older flock mates. Our hens and pullets aren't "tame", but they trust us, and seem to know us. Gathering up a hen or young pullet in my arms, to caress her very soft plumage and speak in a low voice to her, is something I like to take time for.
It seems that most of the eggs in our coop are laid in the morning hours...in fact, I read that hens lay during daylight hours...so if the is ready to lay, but it's dark out, or dark in the coop, a hen will wait to lay her egg until morning light. Anyway, our hens get to hunt and peck and groom themselves outside in the grass and flowerbeds, usually later in the day. They absolutely love being outside. At dusk, they return to the coop to eat and roost.
I'm headed outside now, too. It is a beautiful sunny fall day on the farm. Sallie