It may be true... that I have turned a "home feeding solutions" thread into a "feeding your chickens...aloned in the woods, with nothing but a loin cloth..." thread; however, only now have we exhaused all resouces

. Without going into the extreme one may always wonder what may have been.
The problem with feeding a chicken human food, in order to produce human food, is that it is terribly inefficient. A chicken will eat from 1/4 to a 1/3lbs of feed a day, in order to produce an egg that weighs an ounce or so. The reason that it is so expensive to keep chickens, is because unlike the other animals that we keep, we feed chickens human food.
It is useful to keep goats... because goats eat grass (which is mostly useless for human consumption) and produce milk (which is great for human consumption). The rabbit too, the rabbit likes grass.... and I like rabbit

. This works, only because we are feeding animals what would otherwise be useless. Obviously, to feed your goat oatmeal, just to produce milk, would never be efficient, nor practical.
In todays world, I buy my feed from the store. It is cheap, and easy. However, this would not have worked in the days of Stalin... and for all that we know, it may not work tomorrow either.
Unfortunately, if wal-mart ever runs out of food. People will be forced to eat their chickens, rather than to feed them 1/4lb, in order to produce an ounce.
Also, there is no reason that even in todays world, a person couldn't feed their chickens for free... or rather, to feed their chickens what works for chickens.
Looking at the historical record, I would argue the case that "feeding a chicken human food in order to produce human food" is not at all "inefficient." It's what was done for thousands of years.
Look at it this way. Much of farming throughout history has been about growing staple crops (providing carbohydrate calories, in the form of grains, usually). Mostly this was subsistence farming, and most people ate what they grew, or what their neighbors grew. As anyone who farms knows, the weather and a million other uncontrollable variables affect the grain yields from year to year--and if you are a subsistence farmer, you need to plant a little extra to take this into account, because if you don't have ENOUGH one year you could very likely starve to death, so you end up routinely have a surplus, because it's better than being dead. This is fine, but it just means that the upshot is you generally have more of your main staple (and maybe other things too) than you can use. You keep a small flock of chickens (relative to the size of your farm), which range completely freely, supplying a small amount of high quality animal products for you to eat, to enrich your grain-based diet. You feed them a little of your surplus grain every day--which is no skin off your back, so to speak, because you always have a little bit of extra grain. Something that is of little use to you (surplus grain), is turned into something very valuable (a little protein and other nutritrion from free-range eggs and meat). Furthermore, the chickens forage for all the rest of their feed--in manure piles from your grazing animals, in your midden heap, in the woods, in the grain fields where they glean fallen grain, in the barns, pastures, woods, etc. So you don't have to supply grit, oyster shell, drinking water, or anything else. The chickens reproduce themselves without your help, as a true landrace does, and while you might do a little selection through culling, when and if you have the time, you don't really need to because natural selection does most of the work for you. It's a complete win-win for everybody and hardly "inefficient" in any pragmatic sense of the word. Inefficient systems don't last for thousands of years--call it "the test of time."
So to try to get to sum up my point here--and unless I'm misunderstanding YOUR point, which is entirely possible

--I don't see how feeding chickens "human food" is ineffecient, especially on a sustainable farm or homestead, because aside from what they forage for themselves, you're just feeding them your own surplus produce and household scraps, etc.--bi-products if you will, by which I mean feed sources that are already connected to your other activities and don't require significant SEPARATE inputs. To me that's one DEFINITION of "efficiency." What sounds inefficient to me is the idea of people scouring the woods, peeling pine bark or gathering wild plants or acquiring other feeds especially for the chickens that have no other use to you, the human. I don''t think that's bad per se if it makes the chickens healthy and people aren't destroying pine forests or whatever to do it, but I just don't see how that's more efficient. Yes, BUYING "human food" to feed your chickens may be inefficient, but feeding them on farming surplus "human food," especially such which might be considered "off-grade" or otherwise of little value to people, in order to produce a nutritious diversity of food products, is, as history shows, a very practical approach.
And before anyone gets mad at me for being hopelessly theoretical and out-of-context, I realize also that not everyone on this forum is subsistence farmer--nor am I. That's not my point, of course. My point is that universal principles still apply. In a sense I think part of what makes chickens easy to keep and has made keeping them practical for millenia is the fact that they eat a diversity of things and that they can eat most of the same things that people eat and get by quite nicely on the same staple foods that people can (again, historically, mostly grain, but also this could be potatoes, squash, cassava, etc--me, I don't grow grain, having neither the space, nor the ideal growing conditions, but I do grow with ease many other starchy staple foods). Sure, there are important nutritional differences between man and chicken that are not to be overlooked, but from an everyday standpoint of figuring out what they can eat, not all that different. And how convenient for us humans!
Those are my thoughts on this, anyhow...