Very good and realistic numbers. Mine is a bit less only because I range feed on land that had been planted for feeding chickens with clovers and kelp.
Oh! I should have added the cost of the chick and shipping in that $2.75/dozen. Our costs are less when we hatch our own. Our costs are also MUCH less in the summer due to pasture foraging, but the $2.75 is averaged over the entire year. It's also averaged over her entire life, so it takes into account the fact that there's almost a year of her life when she's not laying at all.