Chicken Math
What is Chicken Math!?
You may have heard the phrase before in forums, groups, or at your local feed store. Maybe you asked for advice on your new chicken flock and a seasoned chicken owner with a somber gaze warned you to beware of "chicken math". But what is "chicken math", and why is it a problem?
Simply put, chicken math is a phenomenon that affects backyard chicken owners where one starts out with the intention of owning a certain number of birds, but ends up owning far more than originally intended. A new chicken owner may plan for 10 chickens, and end up with over a hundred in a short amount of time. How did this happen? Chicken math. Here's how it works.

The Formula
There is a formula to chicken math, and it requires some of that algebra you never thought you'd use as an adult. It starts out something like this:
If the intended number of chickens is x and the actual number of chickens is y, then y = x * "Just in case" . The "just in case" may be "in case some don't make it to adulthood" or "in case some turn out to be roosters." This is how our original plan to have 10 birds became 20 birds. We wanted 10 birds, so we got 20, "just in case..."
But it doesn't stop at 20 birds. Oh no, it never stops at 20 birds. When calculating your chicken math, you also have to consider replacing losses, so y = x(just in case some die) + deaths/roosters * 2.
This is how we originally planned on owning ten chickens, so we got 20, lost ten over the course of a year, and of course, replace the 10 lost birds with 20 more.
The next step in the equation is when you discover a new breed you didn't know about before and just have to have it. So now, y = x(just in case some die) + deaths/roosters * 2 + "Oh my gosh it lays BLUE EGGS"5.
This is how we went from 30 birds to 35, because we wanted blue layers and we wanted to make sure at least one was a hen who made it to adulthood. Naturally, we bought five of them.
...but wait, there's more!
The Math Continues
You might be thinking, "well, 35 chickens is a lot more than 10, but it's still not too bad." Well, we're not finished yet. The formula at this point is y = x(just in case some die) + deaths/roosters * 2 + "Oh my gosh it lays BLUE EGGS"5, but what happens when you decide, "Gosh, it'd be so much cheaper to just hatch our own instead of buying new chickens every time we need them."
So take the formula above, and then multiply it by the capacity of the incubator you bought because hatching your own chicks would be "so much cheaper." Take it from experience, you may think you won't fill the incubator to capacity. You may think you'll only use it once a year. You may think you won't become an obsessive hatch-a-holic who converts the spare room into a giant brooder and makes a home-made incubator with 2,000 egg capacity out of an old commercial fridge and a repurposed thermostat, plunging your family into chaos, destroying your yard, and making your entire community question the housewarming party they threw for you when you moved in, but it's totally going to happen.

Advanced Chicken Math
Of course, chicken math doesn't stop with chickens. Chickens are just the gateway farm animal. After you have obsessively collected every chicken breed on your wishlist, filled your egg basket with every color, manifested a rainbow of fowl on your property, and destroyed your yard, you will glance at a photo of some black India call ducks or a roman crested goose or a royal palm turkey, and you will start to think to yourself, "I just want four or five, so I should get ten... just in case."