Chicken Math Made Easy

.... That is your apples to applies comparison.....
........

Ventilation Space: Standards don't say, except "it needs to be adequate". One book I have doesn't give a set number, only that it needs to be adequate to maintain levels of Ammonia, C02, dust particulates, etc, below levels measured in PPM. I don't have a ruler that allows me to measure that, so that is no help to me at all. Rule of thumb is 1 SF of vent space per 10 SF of floor area.

..........
Speaking of insulation, one book suggests a chickens comb will begin to freeze at +6F. Most likely it was referencing long combed birds like leghorns and roosters, but if you live in USDA climate zone 6a or lower (colder), consider adding insulation to your building. It is not for heat as you think it is. Each bird we have is a little mini furnace radiating several btu's of heat. In a cold climate, a coop can be kept warmer and dryer if the heat generated by the birds is trapped within by insulated walls and ceiling. As much as 10 to 20 degrees warmer depending on a lot of factors, including the number of birds and space they are housed in. Bottom line is if the building is done right, supplemental heat in any form is hardly ever needed, even in climates where outside temps fall to -20 or more.
Apples to Apples maybe?

Insulation..."trapped" heat statement conflicts with 'rule of thumb' ventilation cited....one of the hardest aspects for most folks to understand.

..and some folks DO have to start with coop size then bird numbers due to the area they have available.
This is still my favorite Space treatise for backyarders https://www.backyardchickens.com/a/how-much-room-do-chickens-need
Tho your info on the industry standard definitions for labeling is something backyard egg sellers definitely need to be aware of to inform their customers.

But lots of good info there Howard!

ETA: the title "chicken math made easy" is rather misleading(like most headlines-haha) Most important thing about making chicken math easier is to include Subtraction!
 
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Although I probably sound like it, I'm not offended by any "ick" factor regarding these large farms. Well, most of them anyway. Some probably took the economy of scale thing a bit too far, but in general, they serve a role the same as large vegetable farms do. In many ways, they do the same things. Make nutritious food available to a large number of people at a cost most can afford.

I grew up on a family farm and know how tough things can be, but in growing up on a farm, I also know the benefits (and problems) of having a garden and growing one's own personal food. For me, that now includes chickens. They come with benefits (and problems) that goes beyond the eggs we get. Worth the effort.....at least in my book.
 
Great post, thanks for sharing! Chicken math can be confusing. I agree that "how many eggs" is a really good place to start for most people. But even that can have some unexpected nuances to it. I generally tell people to plan for a bigger flock than they think they want, because it's much easier to downsize later. But then, I also tend to sometimes have a "go big or go home" attitude about things. It's a known flaw (feature?) that I have to keep an eye out for.

The more people I talk to the more I find that keeping backyard chickens is a personal journey. We each make our own decisions. Some of them work out pretty well. Some of them... well, I'll bet most of us has a laundry list of things we wish we had done differently. I am particularly interested in learning how my flock decisions effect my overall investment per dozen. I've never really sat down and tried to do the math, feels too big a job.

In an attempt to do it anyway I'm going to try blogging my way through it piece by piece. My hope is that by the end of the year I'll have a template that will help people really understand the time and money investment that goes into their eggs. I've only been at this for a few years and am still learning. I would welcome any inputs and insights from anyone who's interested.

http://www.nocluckingaround.com

If anybody has any ideas or feedback I'd like to chat via PM here or through my blog.

PapaBear
 
Great post, thanks for sharing! Chicken math can be confusing. I agree that "how many eggs" is a really good place to start for most people. But even that can have some unexpected nuances to it. I generally tell people to plan for a bigger flock than they think they want, because it's much easier to downsize later. But then, I also tend to sometimes have a "go big or go home" attitude about things. It's a known flaw (feature?) that I have to keep an eye out for.

The more people I talk to the more I find that keeping backyard chickens is a personal journey. We each make our own decisions. Some of them work out pretty well. Some of them... well, I'll bet most of us has a laundry list of things we wish we had done differently. I am particularly interested in learning how my flock decisions effect my overall investment per dozen. I've never really sat down and tried to do the math, feels too big a job.

In an attempt to do it anyway I'm going to try blogging my way through it piece by piece. My hope is that by the end of the year I'll have a template that will help people really understand the time and money investment that goes into their eggs. I've only been at this for a few years and am still learning. I would welcome any inputs and insights from anyone who's interested.

http://www.nocluckingaround.com

If anybody has any ideas or feedback I'd like to chat via PM here or through my blog.

PapaBear

Well Papabear if we actually did the math and realized the cost of eggs upfront nobody would get chickens! I am trying NOT to add it up, although my mind keeps a general tally and its kinda high
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I too tend to go big or go home! After many years of, no its out of the question.... The kids and I convinced DH to get chickens tis spring and he agreed, on one condition that the coop had to be nice, must fit in with the rest of the property. So its costing me a ton of $, it has 12" ceilings, a loft.... Lol I am hoping for a few days nice weather to finish it soon and I will do a coop page from start to finish.

Gary form Idyllwild Ca here
 
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More math as it relates to buildings, and closer to the problem of BYC's version of "chicken math", which is expanding flock size. Building size, like flock size, is easy to expand and is something any prospective builder should consider doing.

Why? Assuming a size requirement of 4 sf per bird, a coop that is 4' x 4' would be 16 sf or space for 4 birds (technically not, since you have to deduct the space lost to walls so is more like 3 1/2' x 3 1/2', but forget that for a moment). So by adding only 1 foot along one side to make it 4' x 5', it is now 20 sf, or space for 5 birds. At 4' x 6" it become space for 6. You kept 2 walls the same at 4', and only increased the other two, but increased capacity by 50% from 4 to 6 birds.

Now comes the interesting part. As you gain in size, this process becomes more pronounced. A 6' x 12' coop is 72 sf and space for 18 birds. But by adding only 2' width to the 6' sides, it becomes 8' x 12' or 96 sf and space for 24 birds. Note the linear feet of the 12' side didn't change but by adding only 2' to the 6' sides, you increased capacity 33%. By then upping that to 12' x 12', the space becomes 144 sf or space for 36 birds. In this extreme example, only two sides changed but the capacity was doubled.

Second part and related to the first...…the closer to square you go, the more SF of interior volume per linear foot of wall area. So take a coop that is 4' x 12', or 48 sf or room for 12 birds.

That is also 12+12+4+4= 32 linear feet.

32 linear feet / 4 = 8 So take the same materials used for a rectangle and make it square instead. Then 8' x 8' = 64 sf / 4 = 16 birds.

So by using the same amount of linear feet of wall space, but building square instead of a rectangle, we gained 4 more birds or an increase in capacity of 33% by doing nothing more than rearranging the same amount of materials into a different shape.

The point to all this is to get the maximum bang for the buck, build a bit larger than you think and shoot for designs that are close to square.

When you consider that most building materials come in multiples of 4 and 8 feet, including plywood, siding and such at 4' x 8', it is no surprise that a lot of designs are in the range of 4' x 4', 8' x 8' and 8' x 12'.

The simplest and lowest cost coops to build are shed styles, with monosloped roof, with the high side facing south to the winter sun. Square or close to square rectangles and sizes of 4' x 6' for small backlots (capable of easily handling the enough birds to produce a dozen eggs per week) up to 8' x 12', which is space for enough birds to produce 6 to 8 dozen eggs per week.

There are literally dozens of designs for this sized coop, which once upon a time was nearly universal. Almost every State Ag Dept. had their own design and there was even a US Government Chicken coop design if you can believe that. This style was once so ubiquitous they were even the coop style depicted in the old Foghorn Leghorn cartoons. Go to Youtube and watch a couple and that is what you will see they used in the background.

In the modern era, the Wichita style is a small compressed version of these, so might be a good place for backyarder wannabes to start. Or to go larger, be thinking 8' x 8' or 8' x 12' and be set for the long haul.
 
good info for people starting out
i built 8x 24 hoop coop thinking it would be big enough forever :ya
I now have additional three 8x8 hoop coops..

i found a need to be able to isolate.. breeder, grow outs, bachelors. injured
 

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