What does feed cost you? Iy youre like me, here in chicken country, you can get it for a pretty good price from the mill. I pay $0.18-$0.20 per pound. There in MN, I should reckon you could do close to that. I spent summers there and as I recall, there were plenty of chickens cows and other livestock around.
BTW, you DO NOT have to feed only chicken feed. "All Purpose" livestock pellets can be fed as long as you ensure the layers get their calcium.
We did a little experiment here at BYC a few weks ago and concluded that your own chickens, reared to butcher age of 8-10 weeks, could be raised to compete with store bought. They might be a tiny bit more, but the quality offset any small difference.
When you added in the proper feeding of table scraps as a mash feed, using garden wastes as green feeds and so on, the price could be well be kept in line.
And suppose it did cost you a bit more... where's the harm in that?
Good for you, I say.