Winter happens, and with extra lighting I'm still getting poor egg numbers per day!
Mary
Adding light can help in some circumstances (to photo-stimulate young 20+ wk. pullets), but try as we might, the older birds will still molt and need time to recover. It may happen but I've never had a bird lay eggs while molting. This cessation of egg laying is a necessary rest and rejuvenation period for the reproductive tract. They need a break.
They will restart quicker after molt recovery with some midwinter light.
I keep flocks of similar age together and when most are molting, I don't add light.
About the only time I add light is if a group are coming into POL after summer solstice and they are well over 20 weeks. That will usually be the last time in their life they will have added light because in subsequent years, they'll need a break.
If I force molted early (like late summer), I'll add light in mid/late December, to restart them and more importantly, to photo-stimulate the roosters.
Commercially produced layers live in black out housing and are on a lighting program that kick starts all the same age pullets within a couple weeks of each other. This allows for maximum egg production for feed input. They will slaughter all the birds about 18 months later. It is necessary for them to install a new batch of perhaps a 100,000 to half million birds every couple months in a different barn and in this way they can meet the demand for eggs year-round.
This isn't how most non-commercial chicken keepers do it.
IMHO, 16 hours isn't necessary and may even be overkill. Unless one is keeping chickens closer to the poles, perhaps Alaska or Norway, they'll never experience 16 hours of natural light.
I've experienced poultry production at several latitudes. At the equator, there is just over 12 hours of sunlight year round. Chickens are chickens and they lay just as well there as in more northern or southern latitudes. Those near the equator may experience molt at more various times of year, but they still need to grow a new coat and have a reproductive rest.
Right now, Costa Rica has about 11 1/2 hours of light and at winter solstice will still have about the same light vs. dark each day. In June, it is about 12 3/4 hours of daylight.
At my house, we're at about 9.5 hours of day light now. In late June, we have just under 15 hours of light. At no time, do they naturally experience 16 hours of light.
Perhaps your poultry person is considering a more robust stimulus for egg laying by suggesting that much light. But more importantly, regarding production, it is the seasonal relationship between light and dark periods. Chicken's pineal gland detect whether light is increasing vis a vis dark period. They can even detect changes if they are blind and production of those blind birds varies accordingly.
