Mist, there's actually still a lot of nutrition (and other stuff) in eggs even from hens that are being kept in abominable and deplorable circumstances. Why? Simply because of the importance in biology in regards to 'reproduction' and offspring related matters.
A good example is lactation in human females. It's amazing, actually: As long as a minimum of caloric intake and hydration is being provided, the human body will produce milk for a hungry baby even in dire circumstances, just because of the way we evolved since there is almost nothing as important in biology on this planet as the drive to survive and the functions of the body to not only survive, but ensure the survival of offspring, in this case our children. You can have horrible circumstances of people sitting in refugee camps and not having a place to sleep, but as long as the physiological basics are met, a nursing mother for example can ensure the survival of a baby, even when no luxury microwaves are around to sterilize equipment.
Hens and eggs are similar since that egg (when fertilized) supplies the chick with nutrition, protection similar to a womb, and therefore ensures the survival of the species. You could say that there is a 'level' of chemical makeup off an egg that will not go lower as absolutely necessary since the survival of a species is dependent upon an egg.
Of course horrible surroundings and lack of adequate nutrition can change the makeup of an egg. And the truly insidious thing is that farmers who depend on mass farming actually went more into the directions of creating the 'designer egg', ie, feeding the chickens a diet designed to raise the protein, vitamin, mineral etc content while trying to lower the saturated fat content, cholesterol etc.
So in essence you could have hens that are being fed am incredible diet designed to produce the healthiest eggs possible, while at the same time some hens themselves are being kept in deplorable conditions.
Luckily though the public has developed more of a consciousness about these things and now it's pretty easy to find eggs in stores that are the result from different farming approaches.
You can chose between free range chickens, pasture raised, certified antibiotic free, grain fed, grass fed etc etc.
In an average US grocery store you can find at least two, or tree different eggs that landed on that shelf through different farming methods.
So yes, at this point in time it's actually fairly easy for the majority of people to support humane farming methods since most of us eat an occasional egg here and there, bake with them etc, so purchasing these eggs is a lot more affordable than organic vegetables, for examples.
I have been a Pescetarian first - no meat with the exception of occasional fish. Then I moved into full ovo-lacto vegetarianism and haven't eaten meat in 13 years.
I have several medical conditions and have to keep a close eye on my daily protein and vitamin intake - and eggs are still a perfect addition with their protein, iron, vitamins and minerals. I'm hoping that one day my body won't need vitamin d and iron from the pharmacy, and I'd much rather eat a bagel-egg-cheese sandwich than sit in a hospital for these infusions, for example.
Anyway, that's all kinda OT, but Mist raised an interesting question in this thread - how healthy can an egg be from mass produced farming methods? Biological necessity is the answer.
On a side note; I try to avoid leather wherever possible, be it watches, planners and calendars and other things, seeking out leather alternatives wherever possible, or at least buy certain things second hand in order to not add to the first market demand for leather goods.
And thank goodness that we now have high density fleece, down alternatives that are great for allergy plagued folks and boots to keep us warm in winter that don't depend on animals giving their lives for us.
But that of course is a luxury many people just don't have yet, since historically a couple of chickens provided humans with feathers to sleep on, eggs and meat, while they also kept the grass short and kept the yard free of insects and even mice since chickens are actually omnivores and not vegetarians as many people believe.
A friend of mine once had a chicken coop- he didn't slaughter them.... But we enjoyed their incredible eggs and they were actually adorable and sociable, two of them always greeted us in excitement coming up their driveway. They'd even jump on your lap, you could even pet them. I love these birds and would love to have a coop myself one day.