My two new hybrids have just started laying. It's reminded me how amazing eggs are, but how little most people (including myself) know about them.
For example, how does a hen actually produce an egg and how does an embryo inside the egg develop into a chick, at what age does a hen start laying and what is the best way to store eggs?
Here are the answers to some frequently asked questions:
When does a hen start to lay?
A hen usually starts producing eggs at about 19 to 24 weeks. This is the time they reach sexual maturity. The actual age an individual hen starts laying varies due to many factors, such as diet, stress, breed, environment and light.
What is each stage in a hen's development after hatching called?
There are many opinions and definitions on how old a female chicken can be when she is a chick, pullet or hen. However, this is the most common view:
- Before they start to lay they are a pullet (a female chick is also a pullet, but most people only call them pullets when they are sure they are females because with most breeds it is impossible to identify the sex of the chick when they first hatch, unless you have sex-linked chickens *post about sex-linked chickens and hybrids coming shortly*, but basically with sex-linked birds the male and female chicks are different colours.)
- At about 18 - 24 weeks they are known as Point of Lay Pullets (POL), and this is usually the age that breeders and suppliers sell their adult birds.
- After they have started producing eggs (they have reached sexual maturity) they are usually known as a hen. However, opinions, of course, differ greatly and some say that they are not a hen until they are a year old. Or, they are not a hen until they have been laying for 4 or more months, or when they go through their first moult.
How often does a hen lay?
A hen can only produce an egg every 25 hours, so about one a day, but it depends on the breed and age of the bird. Usually hens are most productive in their first 2 years of life, and then their egg productivity starts to decrease. Hybrids lay more than Pure Breeds. Some hybrids, such as the Gingernut Ranger or Black Rock, can lay up to 300 eggs a year. See this article for more information on the best egg-laying pure breeds.
Do you need a cockerel for the hens to lay?
No! It is widely believed that hens will only lay eggs if there is a cockerel present. However, hens will lay even if they have never even seen a cockerel before. A cock/rooster is only needed if you want fertile eggs to hatch, as eggs will not hatch if they are not fertile.
How is the egg formed inside the hen?
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| Diagram showing the position of the different parts of an egg. Credit: Birdbrain99 (author) |
When a female chick hatches, she has thousands of very small ova, which are stored in the ovary. She releases these into the oviduct when she reaches sexual maturity. An ovum is an undeveloped yolk; the albumen (white), the membrane and the shell are added as the yolk travels through the reproductive system. This whole process takes about 25 hours. If the hen has sperm (from the cock bird - she will only have sperm if she mates with a cock/rooster) is added to the yolk just before the albumen encases the yolk. The egg passes out of the hen through the cloaca, or vent. This is also used for excretion, and both the large intestine and the oviduct lead to the cloaca but as the egg is released, the hole to the large intestine closes up so that the egg is not contaminated by faeces.
How long does an egg take to hatch?
Chicken eggs normally take 21 days to hatch, but various factors influence the hatch date, such as temperature and humidity. The eggs can be stored for up to 7 days before incubating.
What temperature and humidity do the eggs need to hatch?
It needs to be about 37.5 degrees Celsius (99.5 Fahrenheit). There are many different opinions on humidity, but the accepted idea is 40-50% from day 1 to day 18, and then 60-80% day 18 to hatching (usually day 21).
How can you be sure the eggs are fertile?
The eggs will only be fertile if the hen that laid them has been mated by a cock. It is unlikely that all of the eggs will be fertile. Cocks have 'favourite' hens, and may not bother mating with the others, or sometimes the hen doesn't get caught. However, a cock can fertile many eggs with one mating, and the sperm will stay in the system for up to three weeks. To check if an egg is fertile, you can use a technique called "candling". This only works after the egg has been in the incubator (or under the broody hen) for about 10 days. It is done by shining a bright light, such as a torch light, through the eggs. If the egg is fertile, blood vessels leading from a dark central spot (the embryo) should be visible. If the eggs is infertile or has died the eggs should be completely clear when you chine the light through it. If you are sure it is infertile, discard the egg, but if you are unsure, leave it in in case it is fertile. It is best to get hatching eggs from a recommended breeder or supplier nearby, so that you can check their stock and the environment the hens that the eggs are from are healthy. It also means the eggs have less of a distance to travel, as you can collect them. If not, you can order eggs online and have them delivered through the post, but the eggs may not be so fertile, or one might break during the journey.
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| A selection of different coloured and sized eggs. Credit: Birdbrain99 (author) |
She needs at least 14 hours of light a day for maximum egg production. However you can supplement the natural light in winter with artificial light in the coop.
Do hens ever lay misshapen eggs?
Yes. If this is a very infrequent occurrence, it isn't anything to worry about. However, if it is a regular occurrence, make sure your hens have plenty of calcium (in the form of oyster shell grit and supplements) and a good diet of layer's pellets. Young POL pullets often lay small, strange eggs at first, before they get into a routine.
Where do hens lay?
Most coops (see this post) have nest boxes attached. Most hens will lay in the darkest, safest spot they can find, but you can encourage hens to lay in the nest box by placing a dummy egg or a golf ball there at first as they like to lay where other hens have laid. If you have hens free-ranging they may find another place to lay outside, but most hens are happy to come back to the nest box.
Do I need to keep eggs in the fridge or what other ways to store them are there?Many people keep eggs in the refrigerator, but this is unnecessary. In a fridge, eggs in fact deteriorate faster because of the constant change in temperature when you open and close the door. Eggs can be stored at room temperature in an egg box or you can use an egg ramp. Egg ramps are good because you use the eggs at the bottom of the ramp first, and place the new ones at the top so you are not eating very fresh eggs and leaving the older ones to rot. Eggs can be stored for a very long time in a cool cellar or basement, but eggs stored at room temperature can be kept for for weeks. If you are unsure whether an egg is still fresh, you can place it in a dish of water. If it sinks to the bottom, it is still fine. If it floats or is on it's end, it is bad.
Never wash eggs before storage because this removes the protective outer layer on the eggshell and therefore bacteria can enter the egg and cause you to be ill. If you do get a soiled egg, use a piece of kitchen towel to remove the dirt as much as possible, and then when you come to eat it you can give it a quick rinse as long as you use it straight after.
Many of the guidelines as to how long eggs last is about shop bought eggs, but shop bought eggs have already been stored for days or even weeks before they are sold!
Once you have refrigerated an egg, do not then store it at room temperature as the protective coating will have already been removed by being in the fridge.
