OK, your seemingly regularly egg-producing hens have stopped laying; there can be many reasons for this:
1) First of all, hens are not machines, if they miss a day or two, who cares?
2) It takes on average
25-26 hours from start to finish to produce an egg, if your hen stops laying, you need to look back at least one day before the last normal egg to find the stressor.
3) Stressors can include (list not exhaustive)
- Shock/fright (did an intruder come into their run - next doors cat, a wild visitor, visiting family etc)
- Change in flock dynamic - did you introduce new birds, did a current bird die, have chicks come into lay, has your cockerel reached maturity and started to tread?
- Change in food - have you changed food brand, changed from mash to pellets (or vice versa), have you introduced new treats which you don't normally feed?
- Dehydration - have your hens been short of water (has the waterer fallen over/been damaged/leaked)
- Disease - are your hens unwell... look for changes in comb colour, runny noses, wheezy breathing
- Parasites - do your hens or coop have unwelcome visitors (check betwen feathers near the vent and under with wings for lice and mites; check your coop for Red Mite
- Moult - are your hens coming into moult; this usually happens in spring and/or autumn, and can be as drastic as losing all their feathers at once or losing on or two feathers at a time, but looking generally raggy around the edges
In most cases remedying the situation is simple
- change in food - make changeovers, even between brands, gradually; introduce new treats very gradually... remember treats should not exceed more than 5% of the total diet, which will equate to approximately 6 grams only (based upon an average consumption of 125g of layers pellets per day)
- Dehydration - ensure you have more than one waterer, even if you only have 2 or 3 hens
- Disease - this depends on your outlook I suppose; people who see thier hens as "livestock" may prefer to cull rather than treat; but i think most of us here would go to the vet at least once... most vets would only require to see one bird, then precsribe antibiotics for the entire flock if this is what is needed... remember to ask your vet about egg withdrawal during/after treatment with antibiotics
- Parasites - external parasites can usually be treated with a "spot on" parasite treatment (they are not licensed for poultry, so if you get them from the vet you may have so sign a waiver, and ask about egg withdrawal); internal parasites should be treated with a chemical wormer (e.g. flubenvet) AT LEAST once a year, even if you choose to follow a prophylactic herbal "wormer" the rest of the time
, in others you just have to wait it out.
4) Problems with the "egg laying mechanics" Ex-battery hens seem to be particularly prone to internal laying (leading to egg yolk peritonitis - EYP). This is where once the mature yolk detaches from the immature yolks it misses the oviduct and is, in essence, layed in the internal cavity of the hen. Hens with EYP tend to get a distended abdomen (between their legs) which feels fluidy. EYP is not confined to ex-batts, and both hybrids and pure-breeds can also develop EYP. Once a hen starts laying internally there is little one can do to stop it. If it remains sterile, hens usually go about their normal business, but never lay again. If it becomes infected, it will lead to demise very quickly.
5) Egg binding can also be a problem, especially if a hen is trying to lay a particularly large egg. Egg bound hens will look pretty miserable, and will often stand in a corner, puffed up, with head pulled in, and tail down. Upon palpation the egg may be felt as a hard mass - be very gently doing this, even with external palpation as you may break the egg - and that can complicate the issue a lot. Bring the hen into the house and sit her in a warm bath - believe it or not, even the most flight birds seen to enjoy a warm bath, and will almost certainly relax - for approximately 30 - 40 minutes. this helps to relax the muscles, and you may find she will lay her egg even in the water. After about 40 minutes, you can left her out, and gently pat her dry with towels, then blow dry (on a cool/warm setting - not hot). to finish her off. Put her in a clean box (a cat carrier is ideal) with clean bedding, and put her somewhere dark and warm and draft free. We are doing all of this to help her relax. If after 24 hours she still hasn't layed, a trip to the vet may be in order.
6) Taking a break - most breeds, even hybrids, will take a break from laying during the winter as the number of hours of daylight decreased. Some stop laying from their moult right through to spring, some will take a few days off, and some will lay throughout winter, but not as often.
Eggs take a lot of protein to produce, so in times of moult, any protein the hens eat goes into feather production rather than egg production. You can help out your hens by feeding a diet a little higher in protein than normal. The easiest way to do this is to feed chick crumb (18 - 21% protein) or growers pellets (approx 18% protein). Or, you can add crushed soy beans (a little at a time), or feed a few meal worms. If you choose to, you could also try beef cat or kitten food (wet).
The addition of a poultry tonic (e.g. Poultry Spice) to the food can also be helpful at this time.
Remember that there are exceptions to every rule, and your Black Rock (which generally lay approximately 280 eggs a year) may ever only lay 100 eggs a year!
Remember also that, like a human female, a hen is born with a finite number of yolks, and the faster and more often she lays, the sooner she will deplete the yolks and come to the end of her laying life.
So, in short, if your hen stops laying... don't panic! Give her a check over for ilness or unwanted passengers, but basically, be patient