I have 15 hens, 13 of which are prime laying age and physically able to lay. (One lady, best we can tell, has never laid a single egg in her year and a half of life, and the other one is old enough that she doesn't lay much anymore).
I also have two very well behaved roosters.
That makes a total of 17 beaks to feed.
My feathered kids go through a 50 pound sack of laying pellets every eight to ten days. How long the sack of feed lasts is determined by: 1, how much they spill, 2, the time of the year (they eat more in the winter), and 3, how much special treats they get in a day.
My chickens get some kind of special treat just about every afternoon. In the summer, that is usually either the grass clippings after I cut the grass, or it is fruits out of the garden, or it is weeds that I pulled out of the garden beds.
In winter, the treat may be sunflower seeds, or bowls of raw milk that I get from a local farmer, or alfalfa that that local dairy farmer's cows drop around the feeder. (The cows don't do a very good job of cleaning the ground, so my wife and I have gone out there and cleaned up the alfalfa debris off the ground and bagged it for our chickens).
Of course, all year long they get kitchen vegetable scraps when they are available.
After feeding all of this to our 15 laying hens and 2 roosters, we tend to get an average of about 10 eggs per day in the summer, and right now, we're getting an average of about 6 or 7 eggs here in the winter. We have gotten as many as 12 eggs a day in the summer, and as low as 5 eggs one day this week. But I'd say the average is about 10 eggs in the summer and 6 to 7 in the winter.
Chicken feed prices are going through the roof right now. I used to be able to buy 50 pound sacks of chicken feed for about $9.95. That was just under a month ago. The last two sacks I bought (yesterday) were $10.95 each. I have been buying extra sacks of chicken feed and storing them in my garden shed because the price is going up so quickly.
I don't think that one can justify city chickens on the basis of egg costs. In addition to the cost of feed, there is the cost of light (14 hours a day) needed to keep up production in the winter. Without supplemental lighting in the winter, chickens will cease to lay eggs all together until spring days get long enough to provide that 14 hours a day of light.
In addition, I just bought my birds a heated waterer since their water kept freezing up, and yes -- despite the fact that many folks on this board swear that you do not have to provide heat, I do provide a small amount of heat on exceptionally cold Memphis nights. That costs money too.
But whereas I can't justify my flock on the basis of reduced breakfast costs, I can justify it in the late afternoon when my wife and I sit outside and watch the birds at play. I can justify it when the rooster comes over and demands I let him eat sunflower seeds out of my hand. I can justify it when those goofy birds go squawking at me or give me the "evil eye."
I can justify it when a broody hen hatches chicks before my very eyes, and is a mighty fine mother to them, I might add.
And yes, I can justify it when I get one of those lovely blue eggs that one of my Ameraucana hens lays, or the green egg that one of my home birthed hens lays. You can't buy a blue egg, or a green egg, at any store in the Memphis area at any price.