Thanks for the perspective. I think my numbers may be skewed because I free range my birds, and they actually eat very little (processed) feed total. I currently have a flock of 26 birds which go through a bag of feed ($8/50lbs) every six weeks - that's only $70/year, plus they pay for themselves well with selling eggs. By raising their chicks, I can sell the pullets at 10-12 weeks for $10 each, and eat the cockerels myself. I figure if I raise an additional 26 birds for 16 weeks, paying $11 for 50lb bag of chick starter, I only pay $33 for those 26 birds, not including potential profit on the pullets. If I ordered meat birds from somewhere else (which I have done in the past), I end up paying much more than $30 for 26 birds (CornishX) plus shipping. Then, those birds went through a lot more feed because they didn't get out and forage around like my DP birds do.
That's just my experience though, and it is probably skewed because my birds free-range as much as they do. I would be interested in the numbers you have come up with.