I think you need to tie your sale price to your cost of feed !!!  Smart people will always pay a lttle more for "Farm-Fresh-Egg's .... 
Alan hit it. First, what does it cost to produce an egg?
Dont know? Work it out per chicken, per pound of feed. Add in all reasonable costs, but keep it simple, for now. I would do it like this:
feed + water (primary) + transport + packaging (secondary) + fees (if any) = Total production cost.
NOTE: If it costs you to sell them by using ads or paying fees as a vendor, then add those. 
You can get as complicated as you want with this, but you are just looking for a solid cost number here. I wouldn't go beyond these.
Okay, so once you know how much a dozen costs you to produce, you apply this next formula to determine your profitable sell price:
(Production cost) x 1.618 = profitable sell price.
[[This is the simple way.]]
BUT, there's one more step. Decide what you're selling. Are you selling eggs or, "Naturally raised, Fresh Eggs, just like Grandma's"..... 
See the difference? It takes the same effort to sell a Chevy, as a Cadillac....
Then, GOand ASK people what they'll pay for such a treasure. 
A price in PA can be different than a price in CA, as illustrated. The point is, markets vary for your product. SO find out what your market will give by surveying it.
And remember, "Sell the sizzle, NOT the steak!"
If the natural buy price of your market equals or exceeds your sell price to formula, then your'e making money!