Easter is just around the corner and, while many of us will be indulging in eggs of the chocolate variety, we think the humble chicken egg is more than worthy of our attention at this time of year too.
So, how do our humble hens produce an egg every day? Let us walk you through it…
Of course, the hens rehomed by the British Hen Welfare Trust are some of the best egg producers because they have been bred that way to ensure peak production and consistency of yield.
Warren hybrids as they are known carry little spare flesh when compared to broilers who are bred purely for meat, meaning all her energy is put into producing the tasty eggs we pick up from supermarket shelves every day. When her egg laying slows down a little, or egg quality decline slightly, at around 18 months she is sent to slaughter – that is, unless rehomed by us and sent off to a free-range retirement (although, sadly, only 1% of the UK’s laying flock is lucky enough to enjoy this fate).
Domestic fowl are now the fourth most popular pet in the UK with around 1.6 million of them roaming in back gardens up and down the country. That means thousands of households out there are waking up to freshly laid eggs for their breakfast – lucky things! If that’s you, and you often wonder just what goes on leading up to collection of that perfectly packaged egg, we’re here to unpack the process.
Eggcellent eggs
Hens have only one functional ovary – the left one. The ovary contains follicles of differing sizes and maturity. When each follicle matures, it is called a yolk or vitellus. The yolk travels from the ovary into the oviduct.
The first part of the oviduct is the Infundibulum, this is where the egg stays for roughly 15 minutes. If the hen has been mated this is where fertilization takes place. Beware! If you plan to breed from your girls, it is important to know that sperm can survive in the oviduct for as long as four weeks.
The next part of the oviduct is the Magnum where the egg remains for roughly three hours. The white is generated here. Passing down the oviduct the egg reaches the Isthmus and remains for one hour while two membranes form around it.
Next comes a 24-hour period inside the uterus – the shell is formed at this stage. The final stage is the cloaca. With the help of the hormone Arginine Vasotocin which induces uterine contractions the egg is laid.
How many eggs will she lay?
You’d assume this is an easy question to answer – one a day, right? Well, in theory, yes, but there are lots of factors affecting egg production, and your hen’s delicate balance can be thrown off easily.
A hen in her prime laying period between 20 weeks of age (point of lay) and 78 weeks of age (end of lay) would be expected to produce around 300 eggs annually. Within that time, she will also have periods of rest in her cycle when laying briefly stops. Happily, most hens continue to lay after 78 weeks.
The humble hen egg is designed to be an ideal incubator and nursery for a growing chick embryo. The shell is porous – typically around 7,000 pores in the calcium carbonate shell allow air into the embryo. For this reason, it is not recommended that eggs are washed if floor-laid as bacteria can be introduced via this route. There are strict regulations governing egg production within the egg industry and eggs are not allowed to be sold as first quality if dirty or damaged in any way. Hens need 4g of calcium to produce one egg and if they are calcium deficient, this can affect their laying.
However, with a good diet, lots of regular sun and dust bathing, plus a bit of TLC, hens could lay up to three or four eggs per week.
What can affect a hen’s egg production?
As mentioned, a calcium deficiency is a major factor in a reduction of eggs. Then comes age, and the moulting process.
If your hen is sick or has been through any kind of trauma, this will also likely affect her egg laying for a short while. Rehomers often find that it takes a few days or even weeks after getting their hens home before they begin to lay – after all, the rehoming process is quite a departure from the life they’ve known and it can take a while for them to settle.
Access to light is also a factor, and people often find their hens lay less during winter when daylight is shorter. Roll on longer, brighter days!
Finally, hens need a good quality, balanced diet to get the necessary nutrients for egg laying.
For more information about egg production:
