If you are feeding organic feed, it will cost you about $30/yr per hen if you are able to buy it wholesale. If you factor in the cost of the chicks from a hatchery, constrution costs for coops, and heat and light for coops in winter, you are probably up to about $40.
Assuming a dual purpose breed lays no more than 300 eggs per year, if you get only 20 cents per egg ($2.40/doz) you will only gross $60 per hen per year or a profit of only $20 per bird. If you have 100 laying hens, you will make $2000 for the entire year.
If you are spending at least 2 hrs per day feeding, watering, cleaning and collecting and selling the eggs, you are working about 700 hours per year. Divided into $2000 profit and your hourly pay is about $3/hr. That's assuming you are not sitting at a farmers market for six hours twice a week to sell the eggs.
Do you really want to work for less than half the Minimum Wage?