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ventilation, a century ago

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by digitS', Aug 27, 2008.

  1. digitS'

    digitS' Chillin' With My Peeps

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    I've been looking for information on small coop ventilation and posted some ideas on this thread a couple weeks ago:
    https://www.backyardchickens.com/forum/viewtopic.php?id=79375

    Then! This weekend I was loaned some USDA bulletins from the last century. One called "Poultry Houses and Fixtures," (1934) has very little info on ventilation - install wall vents, use windows and curtains, build copula on roof. But, it's the "Dairy-Barn Construction" (1923) that has just a little information that may be helpful to others with small coops.

    Keep in mind that dairy barns, even in the 1920's were considerably larger than what anyone is going to have in their backyard for chickens. The system referenced is named for F. H. King of the University of Wisconsin and was used for decades. You can actually find a little about the ventilation system and Professor King online. The system relies on tight building construction when air isn't entering anywhere but the inlet vents. Some of these barns were very well built. Here are 2 points that seem appropriate:

    First of all, multiple inlets for fresh air better distribute fresh air, however, if these vents are on opposite sides of the building - drafts may occur. Wind will move air in on one side and out the inlet vents on the other. Those inlet vents will have become outlet vents even if there is an outlet elsewhere. This problem can be overcome by using inlet flues but that discussion goes beyond this one. It seems to me that a simple remedy is to put inlet vents on one side of the coop, only. "Poultry Houses and Fixtures" suggests inlets just above the dropping boards and that's probably a good place.

    During hot weather it makes sense to have the outlet vent just below the roof. Hot air rises and since most of the intent is to cool the building - the hottest air should be vented.

    During cold weather, ventilation (mostly of moisture) is still necessary but warm air should be kept inside the building. The way King found to do this was to extend a flue all the way down nearly to the barn floor (12 to 18 inches above). Above this flue opening, warm air generally stayed put but air near the floor (think manure) rose in the flue and exitted thru the roof.

    The way I can see this working for the coop is to have an opening in the roof (or near the roof) that would ventilate the coop throughout the year. Attach a flue to it that extends all the way down within a few inches of the floor during the cold months. Some kind of damper may be used during the coldest days and nights.

    Farmers 100 years ago built HUGE vertical outlet flues in the center of their barns. A large diameter plastic pipe (6 or 8 inches, maybe) might work better for a small coop. It could be simply pushed on or taken off depending on the time of the year. Something could be done to allow the chickens to stay off the floor during the Winter if they choose to do so.

    Just an old, old idea I wanted to share. How beneficial it could prove to be would require either trial and error or someone with an ag engineering degree to figure out.

    Steve
     
  2. orchidchick

    orchidchick Chillin' With My Peeps

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    Thanks for taking the time to share...........

    That was very interesting. I had a very old dairy barn that was converted for horses in Connecticut and I was amazed at how well it was ventilated. It was set up with a series of flues such as you describe throughout.

    Orchidchick
     
  3. patandchickens

    patandchickens Flock Mistress

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    I think the ideas that your source mentions may be relevant ones for some situations (especially very crowded coops/barns), but, no offence, I would question a number of points regarding their relevance to small backyard chicken coops:

    First of all, multiple inlets for fresh air better distribute fresh air, however, if these vents are on opposite sides of the building - drafts may occur. Wind will move air in on one side and out the inlet vents on the other. Those inlet vents will have become outlet vents even if there is an outlet elsewhere. This problem can be overcome by using inlet flues but that discussion goes beyond this one. It seems to me that a simple remedy is to put inlet vents on one side of the coop, only.

    One observation I would make is, chickens are shorter than cows [​IMG] A light breeze moving across the top of the coop is not so much of an issue for chickens. Furthermore, with most of us keeping chickens at a lower stocking density than most commercial operations (even commercial operations of the 1920s, I would strongly betcha), we don't need as much ventilation per square foot of building, and thus there's less wind problem.

    Finally, the draft problem can be already pretty much entirely solved by only opening the amount of vents that the weather warrants, and if you're in an especially windy exposed location by installing a hood or baffle over one or more vent, to blunt the wind.

    Putting vents only on one side of the coop does not give you particularly good ventilation of the whole building; nor does it give you particularly good passive ventilation period. It may well be quite appropriate for ACTIVE ventilation systems such as fans (indeed I can see where you would want your outlets on the usually-downwind side of the barn, to avoid strong winds buggering up the system, and on reflection that does seem to be how at least one fan-ventilated barn I've worked in was built). But fans are both overkill and IMHO pretty inappropriate as your mainstay of ventilation in a backyard chicken coop -- you can achieve the same result with much less expense, work, electric bill and fire risk by just building good passive ventilation (on multiple walls) and then you do not have any worries about what happens to air quality when the power fails.

    "Poultry Houses and Fixtures" suggests inlets just above the dropping boards and that's probably a good place.

    I am having trouble figuring out how this is not going to pull the coldest air in just below the roosting chickens' fannies and risk chilling them.

    It may be that in a commercial-type barn in a mild climate, getting RID of heat in the chicken barn is more of a problem than keeping 'em warm, I dunno whether this applies to what your authors were talking about -- but I can tell you that the one place I would absolutely not want to put an essential vent (i.e. one gonna be used in cold weather as well) is right by the roost!

    During cold weather, ventilation (mostly of moisture) is still necessary but warm air should be kept inside the building.

    This may sound nice but I question the degree to which it is desirable in practice. The warm air is the air with the largest concentration of moisture in it. If you vent the coolest air, you vent the least moisture. It is possible that a person might get to *thinking* that this was a good arrangement if their coop was already pretty humid (as it probably was, in that era and since you describe the book as talking about barns that are 'pretty tight'), simply because cold+humid is more of a problem for chickens than cold+dry. But to my way of thinking the solution is not to keep the humid and mitigate the cold; it's to keep things as dried out as possible so that freezing temperatures are not a problem.

    If a person wants to minimize heat loss, a better way would be to pre-warm the incoming air. There are various ways to do this (I haven't actually seen coops that use any but I'm sure some are out there).

    For instance one could run a (large diameter) inlet flue thru a warmish area before it actually lets out into the coop, such as having an upwind-side vent run thru a flue that has a section insulated onto the ground so that it can be somewhat warmed by earth heat and thus enter the coop at a less-cold temperature than it would otherwise. I have not seen this done in coops; the issues that can arise when it is done in houses would not be much of a problem for winter coop use.

    Alternatively, you can warm your incoming air in a large space before it enters the coop. This winter my coop (actually it is an insulated, concrete-floored 15x40 former kennel building) will have the hatch into the 'attic' replaced with a closeable vent (at the top of a tower to keep the inlet well above the insulation), as the attic gets much warmer in daytime than the outside air. I have also built a lean-to run outside the front window, which will be almost-totally covered with clear plastic this winter and hopefully air will heat up in there and can be let into the coop by cracking the window open (b/c hot air rises). Other vents are available too, mind. We shall see how it works. But the concept works for houses (when it's used) and I cannot see why versions cannot be engineered for coops as well, when necessary, which isn't really all THAT often anyhow. (I don't really *need* it, it only gets to about -20F here most years, I am mostly just foolin' around)

    Another way, if your coop is attached to a larger building such as a real barn, is to have vents into the barn so that at least whenever the barn is pressurized from the wind, its air will go into the coop, and of course that will be warmer than outdoor winter air too.

    The way I can see this working for the coop is to have an opening in the roof (or near the roof) that would ventilate the coop throughout the year. Attach a flue to it that extends all the way down within a few inches of the floor during the cold months. Some kind of damper may be used during the coldest days and nights.

    It's an interesting idea. I can see some potential problems but probably they could be tweaked out of it in time. You will need more total airflow that way, b/c you are removing drier air only.

    It sounds quite a lot more difficult and experimental, though, than just cutting a whole bunch of ventilation areas, which can be individually closed or opened to suit the season and weather, some hooded/baffled if you get fierce winds, and just doin' it the usual way. Difficult and experimental are not bad things [​IMG] but it's not obvious to me that the flue business will really work any much better.

    No offense meant, just discussing the concepts,

    Pat​
     
    Last edited: Aug 28, 2008
  4. sunnydee

    sunnydee Chillin' With My Peeps

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    Okay...I will ask it..what are flues?
     
  5. digitS'

    digitS' Chillin' With My Peeps

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    Quote:In this case, flues are tubes used for the movement of air.

    Steve
     
  6. sunnydee

    sunnydee Chillin' With My Peeps

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    Okay...thanks digitS
     
  7. lhowemt

    lhowemt Out Of The Brooder

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    I'm in the pre-planning stages for building my first coop this spring. I just picked up a book called "fresh air poultry houses", written in the 20's. When's the last time I read a book from the twenties or before? Probably high school, english lit, or something. so it's pretty cool from that aspect.

    I'm wondering if anyone knows anything about these woods open front houses. It sounds pretty interesting, like it might even work. But the book is so much of just repetitive statements about the importance of fresh air and quotes from doctors and such. Makes me kind of think of a laudnum ad, or snake oil ad or such!

    Quite different from a barn design, with just the front windows open in winter, the coop built quite deep with the roosts in the back, and peaked roof, with clerestory windows up there (open in summer). the theory being that with just one large opening, wind/air pressure isn't going to allow for the weather to blow back in there, and provide ideal ventilation with protection from the weatther. Open windows face south.

    I wouldn't consider something like this without the ability to close it up in really bad weather (close front, open upper clerestory), but for our not-eally-that-cold-usually western montana winters, it seems like an interesting idea.

    Thoughts, experience?
     
  8. lhowemt

    lhowemt Out Of The Brooder

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    Bumping back up, I'm AMAZED at the traffic on this forum!
     
  9. Sylvie

    Sylvie Chillin' With My Peeps

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    Thanks for posting this digitS'. It is facsinating how they did things back then. There is much wisdom and ease in how they solved problems. I usually find at least one feature that I can incorporate into my current project.
     
  10. phalenbeck

    phalenbeck Chillin' With My Peeps

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    Cold/vents/coop size/ it was all driving me nuts. There is the old they are just chickens and they are tough, do not worry part of course, but when my chickens went to a part of a large shed--think mini-barn, but they do not have pigs or cows like in the old days. The thought became why not build a shed in the shed and be done with all this thought. I enclosed a insulated box on 3 sides just big enough for them to hide from wind/cold/whatever. Then thought I have 2 groups that really do not like to be together so I built another. Now 2 sleep inside one box, with 8 on the perch most nights, and when cold or they are wet after run time we get up to 5 on the 10 in the box. ----So now my uninsulated vented roof shed does not have to keep me up coldnights. They have a chicken heated box that they seem to have figured out is the place to be when cold. The regular residents of the box seem to sleep close to the door when warm, and farther in when cold. -----I also have been in some well made and thought out barns from 1920-1930 with features I did not understand as a non-farmer. But without a couple dozen cows warming the place up perhaps the insulated box in the shed/barn is and idea for the backyard chicken in a larger building. Or perhaps not.
     

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