Woods Fresh-Air coop build

[Ted Brown]

FWIW

I did the calculations using commonly available online calculators.

Watts to BTU conversion:

1. It is generally accepted that a chicken gives off 10 watts of heat per hour, 14 chickens is therefor 140 watts.
2. 140 watts is equal to 477.7 BTUs per Hour.

BTU heating:

3. Using coop size information provided above the requirement is to heat 36 sq ft of space.
4. I used the following assumptions: Climate Zone 6; poor insulation (many leakages and windows); average sun exposure.
5. The calculator indicates that 2,178 BTU per hour is required to heat the 36 sq ft or 4.5 times the heat given off by 14 birds

Conclusion:

The presence of chickens in a coop will NOT increase the temperature inside.

I do not intend to be "difficult" but I do value accurate information, my apologies to @Beej7.

 

[Beej7]

FWIW

I did the calculations using commonly available online calculators.

Watts to BTU conversion:

1. It is generally accepted that a chicken gives off 10 watts of heat per hour, 14 chickens is therefor 140 watts.
2. 140 watts is equal to 477.7 BTUs per Hour.

BTU heating:

3. Using coop size information provided above the requirement is to heat 36 sq ft of space.
4. I used the following assumptions: Climate Zone 6; poor insulation (many leakages and windows); average sun exposure.
5. The calculator indicates that 2,178 BTU per hour is required to heat the 36 sq ft or 4.5 times the heat given off by 14 birds

Conclusion:

The presence of chickens in a coop will NOT increase the temperature inside.

I do not intend to be "difficult" but I do value accurate information, my apologies to @Beej7.

This is the most illogical unrealistic thing I’ve heard all day. And I keep up with the news!

How can one accurately quantify how much energy a living being generates? Life is full of variables, and the majority of those variables cannot be accounted for in any helpful way.

What breed of chicken?
Standard or bantam?
Rooster or hen?
Healthy or sick?
Molting or fully feathered?
Parasites or not?
Free range or commercial fed?
Any high energy treats being fed to them? If so, what, how much and when?

What about the coop? What is it made of? Are gaps sealed? Is the door sealed? Is there caulking? Is there insulation? How much snow is there on the roof? Is it windy, it so, how windy and what direction?

We’re talking about real life here, not computers and statistics.

 

[WI chickens]

FWIW

I did the calculations using commonly available online calculators.

Watts to BTU conversion:

1. It is generally accepted that a chicken gives off 10 watts of heat per hour, 14 chickens is therefor 140 watts.
2. 140 watts is equal to 477.7 BTUs per Hour.

BTU heating:

3. Using coop size information provided above the requirement is to heat 36 sq ft of space.
4. I used the following assumptions: Climate Zone 6; poor insulation (many leakages and windows); average sun exposure.
5. The calculator indicates that 2,178 BTU per hour is required to heat the 36 sq ft or 4.5 times the heat given off by 14 birds

Conclusion:

The presence of chickens in a coop will NOT increase the temperature inside.

I do not intend to be "difficult" but I do value accurate information, my apologies to @Beej7.

Can I ask where you got 36 sq ft? To do the calculation correctly, I believe you would need to calculate cubic ft. A 6'x10' coop, if that is what we are talking about, with an average ceiling height of say 6' (guessing here due to the odd shape of the Woods coop) would be 360 cubic feet. From that number you can get a fairly accurate idea of BTUs to heat to a given number, or a given rise in temp.

 

[Ted Brown]

Can I ask where you got 36 sq ft? To do the calculation correctly, I believe you would need to calculate cubic ft. A 6'x10' coop, if that is what we are talking about, with an average ceiling height of say 6' (guessing here due to the odd shape of the Woods coop) would be 360 cubic feet. From that number you can get a fairly accurate idea of BTUs to heat to a given number, or a given rise in temp.

Excellent question, shows you gave careful thought to my post above.

The BTU requirement calculators generally are used to size the heating source in a home; they therefore use square not cubic feet; inbuilt to their algorithms is the assumption that homes have 8ft walls.

I tried to be very conservative in the parameters that I used in my calculation above (originally I used your 6' by 10' by 6' or 360 number); changing that factor results in a requirement of ~25,000 BTUs of heat or 45.55 times the heat given off by 14 chickens.

Even if I had used 6' by 10' or 60 sq feet it would be close to double the heat requirement given by the BTU calculator. A Woods coop does not have level ceilings they are sloped (eg in my 10' by 16' Woods both the front and the back walls are 4' high, the highest ceiling point is 10'); I therefore did a SWAG to come up with my 36 sq ft number. Safe to say I gave every effort to reduce the sq ft number to reduce the BTU requirement given by the calculator. Others may make different decisions than I did but we are talking mouse nuts.

As to the rebuttal that heat (energy) given off by a chicken cannot be calculated "in the real world". It is of course true that there are variables (size, caloric content of feed, etc., etc.) but scientific methods have been developed by well educated people to do just that (companies that make feed for animals REQUIRE accurate methods to calculate appropriate formulations). The original methods for estimating energy expenditure by animals were developed in the '60s and are known as the "heart-rate and water methods". A more recent method known as "dynamic body acceleration" has also been developed. There is lots of information available online describing these methods for those who are interested in fact rather than opinion based decisions.

Again, my apologies to anyone I have offended.

 

[WI chickens]

Excellent question, shows you gave careful thought to my post above.

The BTU requirement calculators generally are used to size the heating source in a home; they therefore use square not cubic feet; inbuilt to their algorithms is the assumption that homes have 8ft walls.

I tried to be very conservative in the parameters that I used in my calculation above (originally I used your 6' by 10' by 6' or 360 number); changing that factor results in a requirement of ~25,000 BTUs of heat or 45.55 times the heat given off by 14 chickens.

Even if I had used 6' by 10' or 60 sq feet it would be close to double the heat requirement given by the BTU calculator. A Woods coop does not have level ceilings they are sloped (eg in my 10' by 16' Woods both the front and the back walls are 4' high, the highest ceiling point is 10'); I therefore did a SWAG to come up with my 36 sq ft number. Safe to say I gave every effort to reduce the sq ft number to reduce the BTU requirement given by the calculator. Others may make different decisions than I did but we are talking mouse nuts.

As to the rebuttal that heat (energy) given off by a chicken cannot be calculated "in the real world". It is of course true that there are variables (size, caloric content of feed, etc., etc.) but scientific methods have been developed by well educated people to do just that (companies that make feed for animals REQUIRE accurate methods to calculate appropriate formulations). The original methods for estimating energy expenditure by animals were developed in the '60s and are known as the "heart-rate and water methods". A more recent method known as "dynamic body acceleration" has also been developed. There is lots of information available online describing these methods for those who are interested in fact rather than opinion based decisions.

Again, my apologies to anyone I have offended.

I understand. My Woods roof height is nearly 10' at the highest point as well, and as you said, the very front and back walls 4', with the portion of the roof directly beneath the monitor windows at approx 6'. That's why I "rounded" my ceiling number to 6'. An approximation certainly, but should be a fairly accurate one.

I can't speak for @Beej7, and don't intend to, but I personally am not offended. I find the discussion interesting.

 

[3KillerBs]

but scientific methods have been developed by well educated people to do just that

It would never have occurred to me, but I suppose when you're raising broilers by the tens of thousands this would factor into the requirements for ventilation capacity.

 

[saysfaa]

It would never have occurred to me, but I suppose when you're raising broilers by the tens of thousands this would factor into the requirements for ventilation capacity.

This. And in trucks sometimes, as well as housing. Also, it is useful for feed requirements.

Also things like differences in heat (or cold) tolerance. If chicks are regularly exposed to higher (or lower) temperatures, it affects how much heat their muscles generate so how well they tolerate heat (or cold). Possibly, it doesn't have to be chicks but that was the study I saw most recently.

That is just the poultry field. Students in engineering and biology sometimes design equipment or studies that incolve measuring heat generation of animals. One of my physiology classes did so with mice. Actually that class had virtual labs the mimicked studies that used to be done in real life.

I also find the whole topic interesting. Irrelevant in many ways for backyard purposes but interesting.

 

[3KillerBs]

This. And in trucks sometimes, as well as housing. Also, it is useful for feed requirements.

Also things like differences in heat (or cold) tolerance. If chicks are regularly exposed to higher (or lower) temperatures, it affects how much heat their muscles generate so how well they tolerate heat (or cold). Possibly, it doesn't have to be chicks but that was the study I saw most recently.

That is just the poultry field. Students in engineering and biology sometimes design equipment or studies that incolve measuring heat generation of animals. One of my physiology classes did so with mice. Actually that class had virtual labs the mimicked studies that used to be done in real life.

I also find the whole topic interesting. Irrelevant in many ways for backyard purposes but interesting.

Yes, it's quite interesting.

 

[Beej7]

Also things like differences in heat (or cold) tolerance. If chicks are regularly exposed to higher (or lower) temperatures, it affects how much heat their muscles generate so how well they tolerate heat (or cold). Possibly, it doesn't have to be chicks but that was the study I saw most recently.

Interesting, there’s another variable that I didn’t include. I dont follow the rules when raising chicks (strict temperature requirements, constant heat lamp, 5 degree reduction in temperature every week, nothing but chick starter feed).

These chickens were incubated, hatched and raised by a hen, inside this coop alongside the rest of the flock. They have absolutely no supplemental heat at all in their life. They were eating bugs, picking through dirt and eating small amounts of herbs and fruit scraps from about day 4. They hatched in early September and had to deal with suboptimal temperatures pretty much their whole life so far. They barely feathered out by the time we started getting freezing temps.

Maybe, just maybe these birds are hardier and able to produce more heat than the sad, abused factory chickens that were doubtlessly used to gather all the numbers and statistics that are being used to quantify the amount of energy a living chicken can generate.

Once again, we’re talking about real live beings here not machines.

 

[Beej7]

If you swap the two thermometers do you get the same results?

Yesterday after work I checked the thermometers with no chickens in the coop and sun shining. Inside was 6 degrees warmer than outside. Then I swapped the thermometers and checked a while later. Sun had set but chickens moved into the coop. 3 degrees warmer inside than outside. Checked again this morning, no sun, full of chickens and 3 degrees warmer inside.

This leads me to believe that the thermometers aren’t exactly equal but despite their differences the coop still is consistently warmer inside vs outside both due to sun shining and due to chickens generating heat.

I wont be doing any more thermometer experiments since none of this is important.