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Chicken Math Explained

“I went to the store for 3 baby chicks without telling my husband and came home with 12. I needed to make sure I got all girls and then one thing led to another. If I don’t answer back to messages - I’m buried in the backyard somewhere”.

“We had 3 hens, then I bought 3 more hens, so now we have 50”.

“ We lost our favorite hen betty today :( , so we went to the local chicken farm and bought 8 more chicks – its chicken math”


If you have said anything along these lines to a friend or posted this on the internet, you were not a victim of chicken math – you just have a weakness for cute fluffball chicks. I’m not saying I blame you – personally I have over 100 birds in my backyard and can totally relate. But never the less chicken math is a real think, and is in fact much different than loosing self control at the feed store.

Examples of Actual Chicken Math: Accounting for improper sexing at hatcheries, Accounting for natural male to female ratio, Accounting for loss, Cost of initial purchase, Flock Housing and Maintenance like coops and feed, poultry first aid, and equipment like feeders, drinkers, nest boxes. All of these things add up just like our crazy way of determining how many new birds we need on a whim.


Cost Factors:

Flock Addition: Accounting for improper sexing at hatcheries

My estimate from my own purchase history is that roughly 30% of all “Sexed female orders” are males. Meaning you pay for 10 sexed pullets and you get 7 girls, 3 boys. Every single time. This is due to two factor: Hatcheries being cheap and saving females to fill orders & hatcheries cannot correctly sex chicks. This is why your Tractor Supply pullet is crowing 4 months in.

Flock Addition: Accounting for natural male to female ratio

If you are purchasing straight run chicks you can look at things two ways. Statistically, like the flip of a coin, you always have a 50/50 shot at getting a boy or girl. But truly it goes deeper – science shows through research connected to livestock breeding that the males sperm determines the sex of the offspring, and that some males have a history of siring a higher percentage of males or females. Is this genetics or coincidence? We will probably never truly know. But back to the math, we are going to run with the first reasoning and assume if you want to have 5 hens laying eggs 6 months from now, should should probably purchase 10 straight run chicks and cross your fingers.

Flock Addition: Accounting for loss

A fact of life is that birds are going to die. Why? Hold your pants. Parasites, coccidia, bacterial infections, viruses, over administering of vaccinations, the simple fact that chickens don’t get regular checkups like humans – When was the last time you gave a chicken a CAT skan or (pre-mortem) blood test? Cancer, heart defects, dogs, racoons, foxes, hawks, owls, killed by another chicken, eating random stuff, getting into ant poison, and last but not least – the rooster attacked the missus. There are obviously many more ways for an animale to pass but this gives us an idea of what we need to do to protect our flocks and estimate the math involved in our flock loss. Since a portion of our pet birds are going to prematurely die - how we do account for this mathematically? Well unless you have a chicken record keeping book and enough birds in a sample size to accurately measure the probability of loss to each of these and all the other thousand ways a chicken can die – you cant. But how do I account for loss on a chicken farm? Historically - Roughly 10% of each sample population is going to die before year one. On my farm roughly 2 out of every 40 chicks will develop coccidia and pass before I’m able to catch the problem and treat the affected group. Over the past year I’ve seen the for upper respiratory infection about 25,000 time on Facebook chicken groups – so we know this is a deadly disease. Rarer breeds like Deathlayers have been inbred to a higher degree than birds like the Rhode Island Red leading to leg and heart issues. In my case as I have been raising Deathlayers for a little under a year I have seen otherwise completely healthy birds drop dead in a matter of minutes for what I suspect to be genetic and reasons linked to continual inbreeding in the parent stock. But there is good news - After year one the number drops drastically in a clean and well protected environment, so personally I neglect all accounting for death after year 1.

Flock Housing and Maintenance

Chicken coops range from $100 DIY coops to half million dollar facilities but since I’m writing this blog – so I’m going to use my historical cost data on the farm for an example. In addition we all have access to different feeds, supplements and equipment so again – this is just an example of what the actual math is behind the chicken.

Flock Size: 125 Birds separated into 8 coops – My cost on the current stock I have is roughly $12,000 including the birds I started with and retired, in addition to new blood I have added to avoid inbreeding lines. I’ll explain why this number is so high below, but for the backyard chicken tender – 10 birds will run you between $50 and $1,500 depending on breed and age at the point you purchased.

Coop Size: 8 – 10’x10’ coops with 8 attached 30’x10’ runs made of treated wood and welded wire. My facility ran me just over $19,000 including wood, wire, electrical wiring, water lines, brooders, nest boxes, dust baths, drinkers, feeders, lighting, and amending the floors.

Flock Demographics: I keep rare breed chickens (such as Ayam Cemani, Deathlayer, German Bielefelder, Barnevelder, Ameraucan, etc.) meaning at some point I paid roughly 20x more per bird on average for high quality stock than most backyard chicken owners when starting their flock. So again one can spend $5 or $100 on the same animal but different appearance and origin. This is a variable you’ll need to account for when doing your chicken math.

Feed Quality: Purina, Nutrena, Dumor, MC Feed, and so on are all different prices and qualities. Enter chicken math. For the most part you will feed each bird 1/3 of a pound per day at full size. Personally I choose to feed my baby chicks Purina, my adult breeders Nutrena, and my table egg laying hens feed from the local mill. At $20 bucks per 50 pound sack – that is 150 feedings. So in my example that is a little over 1 days worth of feed for $20. At our farm we also free range some birds, supplement the pens with grass clippings, table scraps, and toss in vegetables from the garden periodically. So for a small scale backyard chicken keeper you can get away with very little on the feed bill if you’re creative.

Flock First Aid:

Corrid, Tylan, Oxytetracycline, Denegard, Rooster Booster and Electrolytes, blue-coat are all things I keep on hand for poultry treatment. Occasionally I’ll need something for mites or ticks like Elector PSP but that is not often because of the dust baths. All of this adds up and my last year’s medical bill ran a little over $600 – but that being said less than half of these products were used in their entirety so I can use these products for the coming years barring shelf life issues.


So with all this being said here are the final numbers for my flock of 125 rare breeds in fairly luxurious coops: Flock Cost: $12,000 for current stock (125) not including retired birds

Coop and Run Cost: $19,500 for the 3,200 sqft facility

Equipment: $3,200

Feed Bill: $16 per day or $5850 per year

First Aid: $600

Total: $41,150 for 125 chickens, or $329.20 per chicken. That’s why you need chicken math – so you don’t end up like me 

For an economy version:

Flock Cost: $5 per bird, 15 birds = $75

Coop and Run Cost: DIY or Feed store Coop and additional run = $450

Equipment: Drinker, Feeder, Nest Boxes = $150

Feed Bill: 5 pounds per day = $2.00 per day or $730 per year

First Aid: Corrid, VetRX, Electrolyes = $50


Total: $1,455 startup cost for a small flock, or roughly $97 per bird. So believe it or not that $3.99 pullet is going to cost you almost $100 by the end of the year if you’re just starting out. So do an exercise and tally up what you’ve spent this year on chicks and coop features and tell me and comment below, *laughs anxiously*. When you do or don’t try this for yourself out of preservation, don’t forget to account for those unwanted roosters in your own estimate.

I hope you found this at least somewhat informative and can now differentiate between actual chicken math and an excuse for buying more chickens!

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