I have raised chickens inside and outside the barn since 1998. Inside the barn, they have light in the winter. Outside, in their own coops, they don't. Here are the things I have noticed, which differ from the article.
1. The article mentions that keeping the lights on can provide both light and heat. True. However, lights can also provide safety. Sleeping chickens in the dark won't be able to wake up and see well enough to stay away from a predator, whether the predator has broken into the cage or is just reaching in through the wire to grab them. A small amount of light (I have four bulbs in a 25x120 foot barn) can provide enough light for chickens to alert each other and stay away from a predator. BTW, this is also enough light to stimulate egg production.
2. Hens with combs/wattles, or roosters who have bigger combs/wattles than hens, can be susceptible to comb/wattle frostbite damage if their roost or living areas are overheated in the winter, particularly if there is not enough air circulation and the combs/wattles become damp. The chickens will most likely survive even if parts of their combs and wattles are frostbitten and fall off, but why put them through it? And you definitely will not want to lose the extra points for comb or wattle damage if you have show birds.
3. This is a lot of birdseed: "If you force a bird to lay during the cold months by triggering her endocrine system with extra light, you can also shorten her laying longevity." Both human females and chicken females are born with a finite number of eggs in their systems. However, both stop producing eggs long before they run out. My outside (no night light) hens and inside (24/7 light) hens both slow down in their laying as they get older, and, depending on breed, stop laying altogether around 7-11 years old. Breed by breed, there has been no difference between the inside and outside hens' final egg date in my flocks. This suggests that light plays no role in how many years a hen continues to lay.
4. More birdseed: "The article goes on to talk about the potential health hazards of forcing your chickens to lay during the winter, especially if you are forcing them to lay when they really need to rest, for example when they are molting." Eggs and feathers are both made of protein. In my experience, adding light for a molting hen does not make her lay. Factors such as the protein level of the feed, and whether the bird is a fast or slow molter, have far more impact on laying. (Hens who are slow molters, replacing just a few feathers at a time, are more likely to lay during their molting cycles.) Adding light for a hen in the winter will make her lay more, but she needs to be able to eat the same layer ration as she does in the summer to produce eggs, plus enough additional feed for "fuel" to allow her to stay warm in the winter.
However, the comments about mites and worms affecting lay are really apropos. Remember that if you are treating for worms and mites, you may want to take a break from eating the eggs until the worm- and mite-killing stuff is out of their systems. That said, while you are waiting, you can hard-boil or scramble the eggs for the chickens to eat, so they won't go to waste.
Also, it's true that heated Teflon coatings put off gasses that are hazardous to birds and all pets, and to us, too, although it would take more to affect someone our size. Ok, my size...don't want to offend anyone!
I cannot vouch for the red vs white light comments, since I have used both (based on what's on sale) and have not noticed any differences.
