Backyard Chicken Calculator

Getting an answer takes nine quick entries, and every one of them is a number you already know or can check. The calculator works out your eggs, your feed, your cost per dozen and whether the flock pays for itself.

1. Type how many laying hens you keep.
2. Type how many eggs each hen lays in a week. A good laying breed averages 4 to 5 in its first two years.
3. Type the feed each hen eats per day in pounds, the size of the bag you buy, and what one bag costs.
4. Type your other monthly costs, your setup cost and how many months to spread it over, and the store price of a dozen eggs.
5. Press Calculate, or press Enter. The cost per dozen appears first and large, with monthly feed cost, savings and payback below. Press Reset to clear the form and start over.

Three formulas run the calculator. Eggs per month = Hens times eggs per hen per week times 52, divided by 12. Feed per month = Hens times feed per hen per day times 30.44, which is the average number of days in a month. Feed cost per month = Feed per month divided by bag size, times bag price.

Cost per dozen = Monthly running cost divided by dozens per month, where monthly running cost is feed cost plus other monthly costs. Cost per dozen with setup adds the setup cost divided by the spread in months, before dividing by dozens. Monthly savings = Dozens per month times store egg price, minus monthly running cost. Payback = Setup cost divided by monthly savings.

The feed figure of 0.25 lb per hen per day is the standard cited by Alabama Cooperative Extension and the University of Kentucky, and Penn State Extension puts egg type birds at roughly 200 to 260 eggs a year, which is about 4 to 5 a week. Both numbers are planning figures, so enter your own flock numbers when you know them. Our budget calculator can help you fit the monthly feed bill into your household budget.

You keep 6 hens. Each hen lays 4 eggs a week, eats 0.25 lb of feed a day, and you pay $25 for a 50 lb bag. Other monthly costs are $10, setup cost $600 spread over 36 months, and store eggs cost $5 a dozen. Here is exactly what the calculator does.

1. Eggs per month = 6 times 4 times 52, divided by 12 = 104 eggs, which is 8.67 dozen.
2. Feed per month = 6 times 0.25 times 30.44 = 45.66 lb.
3. Feed cost per month = 45.66 divided by 50, times $25 = $22.83.
4. Monthly running cost = $22.83 + $10.00 = $32.83.
5. Cost per dozen = $32.83 divided by 8.67 = $3.79.
6. Setup per month = $600 divided by 36 = $16.67, so cost per dozen with setup = ($32.83 + $16.67) divided by 8.67 = $5.71.
7. Monthly savings = 8.67 times $5.00, minus $32.83 = $10.50. Payback = $600 divided by $10.50 = about 57 months.

Feed alone is $2.63 a dozen in this example, which shows why the bag price matters so much. A $5 rise in the bag price adds about $0.53 to the cost of every dozen.

Feed is the biggest running cost, so the bag price is the number to watch. The table below uses the worked example flock, 6 hens laying 4 eggs a week each, with $10 of other monthly costs.

Every $5 on the bag adds about $0.53 to the cost per dozen for this flock. Buying in bulk, cutting waste with a good feeder, and letting hens forage in the growing season all push the number down, but none of them change the math. Only the price you actually pay and the eggs you actually collect count.

The worked example pays back in about 57 months, which surprises most new keepers. The reason is simple. The flock saves only $10.50 a month against store eggs, and the $600 setup cost is nearly five years of those savings. The eggs are cheap once the coop is paid for, but the coop is not free.

Two things shorten payback. A cheaper setup is the first, because every $100 off the coop cuts about 10 months from payback. A better laying rate is the second, because 5 eggs a week instead of 4 lifts the monthly savings.

Production also falls as hens age. A flock lays best in its first two years, then drops a little each year after that. If you spread setup over 48 months but the hens slow down in year three, the later months save less than the calculator shows. Keep the spread honest, and re-run the numbers each year with the eggs you actually collect. Our break-even calculator uses the same idea for a business, dividing a fixed cost by the monthly gain.

Counting only feed is the most common mistake. Feed alone is $2.63 a dozen in the worked example, but running costs are $3.79 and the full cost with setup is $5.71. Quoting the feed-only number makes the eggs look cheaper than they are.

Forgetting winter is next. Hens lay fewer eggs in winter, when daylight shortens, so a yearly average hides a slow season. If you use a spring laying rate all year, the calculator will overstate your eggs and understate your cost per dozen.

The last mistake is leaving out your time. The calculator counts money, not hours. Feeding, cleaning and collecting take time every day, and that time has value even when it never shows on a receipt.

This calculator gives an estimate for planning and is for informational purposes only, not financial advice. Actual feed use, laying rates and prices vary by breed, season and location. See our disclaimer.