I base it off of this:
If 1 bird eats 1/3 pound of feed every day times 365 days is 121.6 pounds per year. Here a hundred pounds of feed costs $23 and multiplied by 1.216 is about $28. If a chicken gives you 250 eggs per and you sell them for $2 a dozen you are selling 20 dozen eggs for a total of $40. That is a $12 profit per year when they are laying good but you should also consider the cost of raising them from chicks which would be about $5 until they start laying.
If 1 bird eats 1/3 pound of feed every day times 365 days is 121.6 pounds per year. Here a hundred pounds of feed costs $23 and multiplied by 1.216 is about $28. If a chicken gives you 250 eggs per and you sell them for $2 a dozen you are selling 20 dozen eggs for a total of $40. That is a $12 profit per year when they are laying good but you should also consider the cost of raising them from chicks which would be about $5 until they start laying.