Why have my chickens stopped laying eggs?

From my experience I have found that the most common reasons chickens stop laying eggs is either a shortage of daylight, illness, moulting, old age or poor diet.
The reality is there is quite a few other reasons for hens to stop laying eggs and we are going to look at the reasons behind a drop in egg production.
The reasons chickens stop laying eggs:
It is still possible to make a recovery and return them to their peak performance. So don’t rush out yet to buy your eggs from the supermarket.
If your hens have stopped laying eggs in spring or summer it is likely that heat, broodiness or illness are the cause.
Check that you have not got a problem with predators or rats stealing your eggs.
Here is a look at the common reasons why your chickens are not laying eggs anymore:-
Insufficient daylight: Chickens are sensitive to day length and in particular the direction in which is it changing. Lengthening days in spring trigger the reproductive cycle and shortening days in autumn bring about a cessation in laying.
Sometimes, your chickens may be getting the right diet and right amount of water but still not laying due to insufficient light. For your girls to lay plenty of eggs, they need lots of NATURAL daylight exposure. At least 14 hours a day of exposure is ideal and hens tend to stop laying completely below 10 hours daylight.
You can put artificial lighting in the chicken coop and set up some automatic timer to switch it offer after a set number of hours. This will help keep your egg production high. However, during the winters, your chickens also need plenty of rest so that they can recover the following year so it is not always advisable to push them to the limit.
I prefer my chickens to take a natural break in the depths of winter.
Yearly moult: If you are producing eggs in a non commercial environment then you will need to budget for the yearly moult when hens take a break for around 6 weeks to change their feathers.
In the Northern hemisphere this starts anytime from October and can last 6 weeks. Actual starting times and duration will vary with your location and conditions.
Moulting can be quite drastic as this Andalusian hen shows. You can see the pins of the new feathers showing.
Moulting is a natural process whereby a bird renews their feathers. As a rule moulting and egg production cannot happen together because of the energy and protein requirements. This means egg production stops while the chicken moults.
Illness: Chickens not laying eggs at all or a drop in production can also point to something more serious such as a sudden bout of infection affecting your flock.
It could be viral or bacterial but either will need treatment even if it is supportive care.
Malformed and wrinkled eggs may be a sign of egg tract infections and most poultry diseases and viruses will effect egg production.
Disease issues can occur on the best kept sites and are not a sign of inappropriate husbandry.
Parasites: Red mites and other parasites can easily be the reason your hens stop laying.Parasites and mosquitoes in large numbers can cause anaemia.

Fleas, mites and ticks all effect the health of your flock. Some of the carry disease and they all compete with the chicken for it's resources. The itching and scratching can distract the birds and cause stress.
The heat: Chickens have a higher body temperature than humans and suffer more in the heat than other farm animals.
Excessive warmth also makes them drink more water which will flush nutrients out of the body.
Keep cool fresh water and provide shade for the poultry. There is plenty of shade from the sun in this image.
The cold: Severe cold freezes water and food as well and can prevent hens free ranging so can prevent them eating and drinking.
A shortage of nutrients especially when they need more to keep their body warm will kick them out of lay quite fast.
When conditions are cold and snowy, it also generally means the days are short as well.
As a rule chickens will cope the cold very well if well fed and watered. This little Wyandotte bantam is taking the cold in her stride.
The diet: Chickens need a balanced and adequate amounts of feed. The egg a bird lays represents a specific quantity of protein, fats, minerals, water and the processing overheads to produce it.
Problems with their diet and feed is a common reason why your chickens may stop laying eggs. Look at your feeding practices and routine and determine if you have recently changed anything. Even the brand of your regular feed that you are feeding your chickens may need checking.
Changing the diet can lead to a drastic drop in egg production or even cause your chickens to stop laying altogether. Diets should switch in a gradual fashion and never an abrupt one.
If your layers are struggling consider adding supplements that are rich in protein and calories like safflower or sunflower seeds.
Feed spoils over time and nutrients oxidise.
I had a friend who managed to get used malted barley from a brewery. He used to keep 600 hens to provide eggs for his milk round here in the United Kingdom. All was fine for about 10 days whilst he was supplementing about a third of the diet for spent brewery grains. Over the second weekend his egg production halved and he started getting thin shelled eggs. The reason is there was only a little protein left in the barley, no nutrients or energy, and it took his birds nearly a month to recover.
Shortage of calcium or minerals: Calcium, Phosphorus or Magnesium are critical for egg production.
The skeleton of a typical modern egg producing hybrid contains about 30 grams of calcium. that means each egg represents about 7% of the birds total calcium reserve.
The skeleton acts as a calcium reserve to supply the demands of egg production and this is rapidly depleted if there is not enough in the feed.
Water: Eggs are about 70% water and A reliable water supply is very important for all chickens, not just the layers.
If your chickens have no access to fresh water throughout the day, the egg production will drop like a stone in no time at all.
Water from ground sources may be contaminated with heavy metals or dissolved salts. Better to use tap or rain water.
Stress: Bad weather and storms with thunder and lightning will disturb their rest.
You know how you feel getting up in the morning without any sleep - pretty crap. Predators prowling around like foxes scratching or rummaging can disturb them every night.
Rough handling or kids or pets chasing chickens can put them off laying. Scratching from parasites is damn annoying at the best of times. If you even seen a bird with bad scaly leg mite it is very distressing. Imagine the unscratched itch.
Not being able to roost naturally or have areas to scratch in or take a dust bath will stress chickens. Fighting with other birds upsets the whole flock. Few things are as disruptive as adding new birds to the flock.
This happy young grower has plenty of space and a perch. Stressed birds will not settle easily
Make sure the nest box is a comfortable place and try adding a few fresh herbs like sage, rosemary or thyme to the hay in the nest.
Cramped or hungry hens will squabble.
The full list of things that cause stress in chickens.
Egg hiding: Free and pasture raised chickens may begin to hide their eggs in covered places like hedges and under thick shrubbery.
In the past I thought I had lost birds and then the magically reappear with chicks in tow demanding to be fed.
They are not hiding them to get one over on you, it is part of their natural behaviour. Listen for the egg chorus or hunt around if you suspect and indulge in some coop training by keeping them in till they have laid their egg for a few days.
Egg eating: Check weather it is actually your hens eating the eggs.
If it is they may need protein, calcium or adjustments to the nests to make them darker.
In depth article on egg eaters and the cures.
Your hens are broody: Egg laying will stop if your chicken is broody.
They may be well fed, have plenty of fresh water and good exposure to sunshine but still fail to lay eggs if they are exhibiting broodiness.
A hen gets broody when it wants to hatch her own chicks. It can happen anytime but in nature it occurs in the spring.
There are various ways through which you can break the broodiness so they can continue laying.
It can take up to 6 weeks for a hen that has been broody to begin laying again.
Age: Chickens live for many years longer than they produce eggs for.
I myself have forgotten how old some of my hens are and it is not unusual for a backyard chicken keeper to have many generations of birds and lose track of how old some birds are.
As in every other type an ageing hen will lose its ability to reproduce and stop laying eggs. This varies depending on the type of chicken and in the commercial production environment chickens are only kept for up to 80 weeks before being sent for slaughter.
In your homestead or smallholding situation you can expect 5 years productivity from quality stock.
Chart giving an idea of the likely decrease in egg production over the years. Hybrids and heritage breeds lay about the same number of eggs, hybrids do it faster.
Egg binding: A thankfully rare condition that physically blocks the egg duct with an egg.
Sometimes it is a broken egg. It normally kills the bird but it can be treated.
The breed is the problem: Certain breeds of chickens do not lay as many eggs as other types.
A modern commercial hybrid for example will lay 300 or more eggs in their first year.
Japanese bantams on the other hand may only lay 160 a year. I have Silkies and whilst the egg is fantastic they rarely lay more than 120 eggs a year.
In finishing I need to say that on a few occasions I have had hens that have never laid and egg. It is rare but there are a few conditions that mean they never start.