My hens have stopped laying

[Bonniebooboo]

I'd be really upset with your caretaker. Feeding and watering chickens is about as simple and easy a job as there is. How could they just drop the ball, knowing that the chickens would suffer as a result?

I hope your chickens rebound quickly.

x 2. That behavior just ticks me off. It has happened to me as well. Geeze!

 

[ChickenCanoe]

I don't think a chicken can survive a week without water.
The person may have come by a couple times or more.
This is the time of year for some birds to stop laying completely regardless of age. The fact that their routine was interrupted as well as reduced food and water likely stressed them enough to exacerbate what happens this time of year naturally.

Even young birds not yet molting may take a break this time of year.
Most breeds will lay like gangbusters for a year to 18 months when they are young. Then in their second autumn they'll molt and quit laying till they grow a new winter coat. They may resume after recovering or they may wait till after the winter solstice when days begin to lengthen. All other things being normal, they will always start up by spring and reward you with their hen fruit till the next autumn and this cycle will continue annually. Each year, the winter break will be longer and longer, summer laying will be shorter and shorter (although larger eggs).
Some breeds hatched very early in the year will molt their first autumn.

Aside from the molting thing, shorter days is a signal to stop producing, longer days is the signal to reproduce.

Since this is the educational thread and to take the mystery out of it, here's a brief rundown of the science.
Light exposure to the retina is first relayed to the nucleus of the hypothalamus, an area of the brain that coordinates biological clock signals. Fibers from there descend to the spinal cord and then project to the superior cervical ganglia, from which neurons ascend back to the pineal gland. The pineal gland translates signals from the nervous system into a hormonal signal.

When light periods are shorter, the gland produces serotonin and subsequently, melatonin. That's the hormone that affects the gonads for sperm production in males and ovulation in females. An increase in melatonin causes the gonads to become inactive.
Photoperiod, in relation to day vs. night, is the most important clue for animals to determine season. And by extension, when to reproduce.
Cold really has very little to do with egg production. The same thing happens whether it is a cold or warm climate.
As light lengthens, the gonads are rejuvenated. The duration of melatonin secretion each day is directly proportional to the length of the night because of the pineal gland's ability to measure daylength. Besides reproduction, it also affects sleep timing and blood pressure regulation.
So as the light period increases, in relation to the dark period, it stimulates reproduction and - voila - EGGS.

In addition to the day vs. night thing stimulation production, I wanted to add a few thing relating to light.
Chickens don't have to see the light. Blind chickens can also detect a change in day length. Light penetrates the skull and thereby is still detected by the pineal gland.

Chickens detect light in a broader wavelength than humans.
Humans detect light in a range of about 400-660 nm.
Chickens detect light from about 300-750 nm.
Human's peak response to light sensitivity is from 550-560 nm.
Chickens have 3 peaks of light perception at 440, 550 and 610 nm.

Spectrum wavelength determines the color of the light.
Humans have retinal cones that detect red, yellow and green.
Chickens have an additional double cone that is thought to allow tracking of movement.
This may be the reason chickens can see the slightest movement of prey (bugs) or predators from afar that we may miss.

Red light at about 650 nm penetrates the skull and eventually the hypothalamus at somewhere between 5 and 50 times more efficiently than blue, green or yellow/orange.
This makes red light vital for stimulation sexual maturity and egg production.
You've seen the sky at the horizon at dawn and dusk and have no doubt noticed it appears red because red penetrates the atmosphere greater than other colors of the spectrum.
So birds outside at dawn and dusk are stimulated more than those locked in the coop at those times without exposure to big openings to the east and west.

Incandescent light is good at producing light in the red spectrum.
CFLs, while efficient, produce little red light.
LEDs produce the most efficient light per watt used and, depending on phosphors used, can be designed to output in virtually any spectrum desired.
You can look for LEDs in the 650 nm range.

Citation:
Prescott, N. B., and C. M. Wathes. “Spectral sensitivity of the domestic fowl (Gallus g. domesticus).” British poultry Science 40.3 (1999): 332–339.

 

[ravingbantha]

The person I hired claims that the chickens were fed, but chickens will eat less when it's a stranger filling their food bowels. I'm curious if this is true.

Granted it does not account for the amount of feed I still had upon my return, nor does it convince me the person was here doing the job properly.