I think that because raising chickens in the back yard is more a hobby or a 'side' than a way to put bread on the table, factoring in cost of labor is misleading because we would have done it anyway - - regardless of the cost, so it's not money invested. Looking at the raw cost of materials...
I just started keeping hens in May 2010, and from a feed standpoint, the girls haven't cost much of anything. A 50# bag of layer feed is around 20 bucks (I think)...the grower feed was a bit more as I recall. I just opened up my second bag of layer feed two days ago, and I think this will last...