Do you have a super Wal-Mart near? Ours always has 18 eggs for a $1. I've had chickens before, and by the time you buy them, build a way to house them, and feed them, I don't think you'll be able to beat 5.6 cents per egg at Wal-Mart.
Eighteen eggs a day is only about 125 grams of protein. You can cut-out half of the eggs, add about 2 1/3 scoops of whey protein, and still be consuming about the same protein. Eighteen eggs is just excessive.