How are chickens eggs formed?

Question

Me and my BF have been wondering how a chickens egg is formed that we eat is it just an embro that has not been fertilised or has it been fertilised but just not been left to incubate. Would a hen still produce eggs without a cockrel.

Answer 1

Chicken eggs are formed starting with the yolk. The yolk is ovulated from the ovary (chickens only have a left ovary). As the yolk travels down the reprodcutive tract of the hen, the thick white (albumen), shell membranes, thin white, then the shell are added around the yolk, in that order. A chicken will lay an egg about every 26 hours. They may not lay every day, but lay in clutches of 5-10 eggs then skip a day or 2, then start another clutch. Sometimes hens stop producing eggs when they molt, which is a rest period for their reproductive tract. After about 2-3 years of age, the egg production and eggshell quality for hens decreases dramatically.

If sperm is present in the hen's reproductive tract, fertilization occurs in the infindibulum (the first part of the tract, right where the yolk comes off of the ovary into the tract & before any white is added). Most of the yolk is actually food for the growing chick if fertilization & incubation occur. There is a small whitish dot on one side of the yolk that is called the germinal disk. This small dot is where the sperm would enter and form the embryo.

Hens & pullets will produce eggs without males around. Most all of the eggs in the grocery store are unfertilized. There have been no males with these females. If the eggs you purchased at the store happened to have been fertilized (not likely), you could not incubate them anyway. There are very different ways of storing eggs that are to be incubated than those that are sold for consumption.

I work and have worked for many years on a university poultry farm. I eat fertile & infertile eggs. There is really no difference, just a few more cells in a fertile egg than an infertile.

FYI:
C#ck or Rooster = male over 1 year
Cockerel = male < 1 year
Hen = female over 1 year
Pullet = female < 1 year

Answer 2

Eggs are not placed inside a chicken, the egg forms inside a chicken. Specifically in the oviduct, all parts of the egg, except the yolk, are formed. The reproductive organ is divided into five distinct regions: (1) infundibulum or funnel, (2) magnum, (3) isthmus, (4) uterus or shell gland, and (5) vagina. The yolk is formed in the follicular sac by the depositing of continuous layers of yolk material. Most of the yolk material is formed within the 7-9 days before the laying of the egg. When the yolk matures, the follicular sac ruptures or splits along a line with few, if any, blood vessels. If any blood vessels cross the stigma, a small drop of blood may be deposited on the yolk as it is released from the follicle. This causes most blood spots found in eggs. After the yolk is released from the follicle, it is kept intact by the vitelline membrane surrounding it. The release of the yolk from the ovary is called "ovulation." After the yolks release from the follicle, the yolk falls into the hen's abdominal cavity. The infundibulum of the oviduct engulfs the yolk with its thin, funnel-like lips. The yolk then enters the magnum section of the oviduct where the dense portion of the albumen is added. The shape of the egg is largely determined in this section. The magnum of the oviduct is divided from the isthmus by a narrow, translucent ring without glands. The isthmus is smaller in diameter than that of the magnum. It is here the two shell membranes form. The shell membranes loosely contain the yolk and dense egg white until the rest of the albumen is added in the uterus. The shell material is added in the uterus or shell gland portion of the oviduct. The shell is composed mainly of calcium carbonate. It takes about 20 hours for the egg shell to form. If the hen lays brown eggs, the brown pigments are added to the shell in the last hours of shell formation. The chalsa, two cord-like structures which keep the yolk centered in the egg, first appear in the uterus. The chalsa also function as an axis around which the yolk can rotate and keep the germinal disc in hatching eggs uppermost at all times. Many people still remove the chalsa when cooking eggs believing it is "sperm" from a rooster. In the last portion of the oviduct, the vagina, a thin, protein coating called "bloom" is applied to the shell to keep harmful bacteria or dust from entering the egg shell pores. The egg passes through the oviduct small end first, but is laid large end first. In the vagina, the egg is turned horizontally just before laying. If the hen is disturbed on the nest, the egg may be prematurely laid small end first. Ovipositioning is the act of pushing the egg from the oviduct. When an egg is formed, it fills the shell completely. Only as it cools to ambient temperature, does the inner portion of the egg contract and form an air cell between the two shell membranes. A high quality egg has a very tiny air cell, indicating the egg was collected soon after being laid and was properly stored. The air cell is usually located in the large end of the egg where the shell is most porous and air can enter easily. The egg then travels the final section of oviduct and is expelled via the vent.

Answer 3

Yes, chickens will produce eggs without a cockerel. Just like you can ovulate without a male. In commercial egg production the eggs are generally not fertilized. Those places that breed the hens that lay the eggs for the production of other egg layers or meat chickens don't generally sell the fertile eggs to the public.

Answer 4

Hens produce eggs without the rooster. Commercially available eggs are usually not fertilized. The egg is actually NOT an embryo, it is what is inside the shell to nourish the embryo if there was one.