A hen (female chicken) does not need the help of a rooster (male chicken) in order to lay an egg. She is quite capable of doing the job on her own, although they will be infertile and incapable of producing a chick.
Hens will lay eggs with or without a rooster. Without a rooster, your hens' eggs are infertile, so won't develop into chicks. If you do have a rooster, eggs need to be collected daily and kept in a cool place before being used so that they won't develop into chicks.
The next question is perhaps, "Why do chickens lay unfertilized eggs at all?" The reason is that the egg is mostly developed before being fertilized. The chicken cannot know in advance whether the egg will end up fertilized or not, so it just has to go ahead and grow the egg in the hopes that it will be fertilized.
When the female releases the egg cell from her body store, she does not know whether a male sperm cell will come and fertilise it or not. But her body still sends them out from the store, just in case there is sperm to fertilise the egg.
Healthy female chickens, known as hens, are able to lay eggs, whether or not a rooster is present. Eggs will be unfertilized if the hen has no access to a rooster, which means the egg will never develop and hatch into a chick.
Normally, roosters will mate without causing any injury to the hen. However, there are certain roosters who may be aggressive during mating or overmate with certain hens. There are also certain breeds of roosters who are known for being more aggressive then others.
Happier Hens
The hens experience a state of order and liberty that they didn't have before. Without a rooster, the most aggressive and dominant hen would usually take over and be a bully. With a rooster, everyone, even the weaker members of the flock, can rest easy.
The ovum remains in the infundibulum for 15 to 18 minutes, and it is here where fertilization would occur if the hen mated with a rooster. However, eggs sold for human consumption are not fertilized (most egg-laying hens never even have a chance to mate.)
A hen does not know if her eggs are fertilised or not. In fact (much like a human) a rooster can be infertile, so a hen's eggs might not be fertilised even if she is in a flock with a rooster. Many modern breeds and commercial hybrid hens will do nothing with their eggs other than lay them and walk away.
A chicken can lay eggs without a rooster because it will naturally go through the process of ovulation in which a yolk is formed, the egg white and shell later develop around the yolk forming the egg that the hen will lay, regardless of fertilization. Therefore, a rooster is not needed for a hen to lay an egg.
A rooster fertilizes an egg by mating with a hen and placing his sperm into her cloaca. However, this is the simplified story of fertilization. Once the rooster's sperm is inside the hen, it goes on quite the adventure before it fertilizes any eggs.
You can tell whether the farm egg you just cracked open for your breakfast is fertilized or not. Examine the egg for the germinal disc, a white spot floating above the surface of the yolk. The germinal disk of a sterile egg contains only the hen's cells and is fully white in color.
Here are the deets: Female chickens have a menstrual cycle that can be daily during certain times of the year. Like women, hens have ovaries. During a hen's cycle, an ovary sends a yolk on its path. The yolk forms what we know of as an “egg white” as it moves through the reproductive tract into the shell gland.
Find out by candling
If the egg is fertile, then you should see a dark spot around the middle of the egg, with some spider-like veins beginning to form around it. If its not, you should just be able to see the shape of the yellow yolk inside the egg, without any signs of an embryo or veins.
Many chickens don't appear to be in pain while laying eggs, but some chickens, particularly young chickens and those laying very large eggs, do show signs of pain. These signs include wheezy, gasping vocalizations while laying and occasional minor bleeding from the vent.
How many eggs can a broody hen sit on? Usually a hen will wait until she's got a reasonable sized clutch, 8 to 12, to start brooding full time but not always.
When you crack open the egg, if it's fertile, you'll notice a small white spot on the top of the yolk about 4mm in width. This is called the germinal disc. This is what tells you if the egg has been fertilised.
There are many studies on the development of an embryo in a chicken egg. According to a study of the Scientific Services of the German Bundestag, embryos can feel pain from the 15th day of incubation onwards.
Back to our original question: with amniotic eggs showing up roughly 340 million or so years ago, and the first chickens evolving at around 58 thousand years ago at the earliest, it's a safe bet to say the egg came first. Eggs were around way before chickens even existed.
Chickens can recognize up to 100 faces
These faces include those of humans! Chickens even remember positive or negative experiences with the faces they recognize and pass that information on to members of their flocks.
Surprisingly, yes - chicken really do seem to recognise their owners. In fact, research has shown that chickens are capable of recognising up to 100 human faces, so it won't take them long to learn who their owner is.
Lettuce, kale, turnip greens and chard are great greens options. Watermelon, strawberries, and blueberries make healthy snacks for chickens when fed in moderation. A few flock favorites include: Vegetables: Lettuce, beets, broccoli, carrots, kale, swiss chard, squash, pumpkins and cucumbers.
A rooster may mate from 10 to 30 or more times per day, depending on the availability of hens and competition from other roosters. However, the number of sperm per ejaculate is seldom less than 100 million which is the minimum required to maintain high fertility.
One reader asked if he could breed his rooster with the rooster's offspring, and the short answer is yes, but only in the short term. In livestock husbandry, what we'd usually call inbreeding is termed linebreeding.
Roosters and Hens
Roosters tend to want to mate with hens as often as they can. It's the rooster's nature to want to reproduce, and most healthy young roosters will mate with their hens as much as possible. It's not uncommon for a rooster to mate between 10 and 30 times each day, according to the University of Georgia.