I think, by my calculations my, 16 girls make me about $10.00/ month, net at 3.50/doz.
I think, if I include the initial cost of the chicks at $5.00 each, the cost of materials for the coop, straight run with 50% roosters, and their feed, they would have to lay about 2000 eggs for me to break even. At 7 eggs a day (low estimate) it would take 285 days. So I think I can say that I will have paid off the overhead in about 250 days of laying.
It's kinda cute...my wife is from a big city in China and she puts the egg money in a coffee can on top of the refrigerator. I tell her it's for a bigger chicken coop for the chickens...because they are the ones with the sore butts.