OK - another point I was trying to make. Could using light in the winter to encourage laying cause cancer and increased infections, etc? But to state unequivocally that it WILL do so, without any resource to back that statement up is more like fear-mongering than sharing helpful information.I see your point.
I think some of the most promising naturalistic alternatives, aside from warm housing and season-appropriate rations, probably involve to breeding efforts to select for winter laying. Some chickens being bred to thrive in chilly, darker weather than others--some happily forage in the snow.
That could be viewed as "messing with nature" i suppose, but to my mind its different: you are selecting animals with biorythms more in harmony with local conditions rather than artificially and radically altering the environment of birds in a way less in harmony with their genetic coding. In a nutshell, It's when there's a dissonance between the genetic memory or evolved niche, if you will, of an animal, and the conditions it finds itself in that tends to promote pathologies. I guess thats MY point...
And of course just letting them rest in winter is a very acceptible option for some. Having a chance to build up new reserves and recover from the stresses of a laying season can mean improved egg quality and vigor once laying resumes...
If such research were presented, I would gladly read it because, despite the fact that someone has decided I'm narrow-minded because I manage my chickens a certain way, I am willing to consider other viewpoints. Also, if I had ever noticed that my winter-laying chickens were in any way less healthy than my non-winter laying chickens, of course I would discontinue that practice.