ventilation question

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by dftkarin, Aug 9, 2008.

  1. dftkarin

    dftkarin Chillin' With My Peeps

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    I am going to have 4 heavy-breed hens in a coop that is probably about 5' x 3.5' x 2.5' tall (with a /\\ shaped roof so that adds a little extra space), with at least 1 window. The run is going to be underneath (with an added tractor attached at times and free ranging each day for a while). I live in New England with sometimes brutally cold winters and hot humid summers. Is there a minimum amount of vented space I should plan into my coop-building plans? I assume I'll have triangular shaped vents at the top of the sides, under the roof. How man square inches of vent should I have and where should I put the vents so that the chickens get plenty of ventilation but no drafts/draughts? I thought I read there was a formula somewhere for this.
     
    Last edited: Aug 9, 2008
  2. digitS'

    digitS' Chillin' With My Peeps

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    It is good to be concerned about adequate air in such a small structure. In a coop with ceilings of 6 or 8 feet, a 2' chicken usually has plenty of air. Having only 6 inches of space above its head is another story.

    The rule of thumb is 3 cubic feet per pound of live chicken, permanent indoor confinement. Virginia Tech During those long Winter weeks when the weather is bad, you may as well consider your chickens "permanently confined" and realize that this is a minimum, anyway.

    If we just go with the numbers you gave us (5' x 3.5' x 2.5'), your coop has less than 44 cubic feet. It would support (44/3), 14 to 15 pounds of chickens. For a heavy breed, that may only be 2 birds.

    Regarding ventilation, the rule of thumb is that hot weather ventilation should be at the rate of 1 air exchange per minute; cool weather at about 1 air exchange per hour. University of Nebraska Probably just open vents would move air fast enuf to do the job for only 44 cubic feet. And, practically any wall opening might allow too much air movement in very cold weather. How large those vents should be must be your question and I think it would vary a great deal by location. An always shaded coop probably would be best. I hope someone in your area can give you an idea.

    What is the possibility for an enclosure below the coop during the Winter months? Perhaps the pen could be replaced by a 5' x 3.5' box with an open top during the time you wouldn't be moving the birds around the yard. You'd have a 2-story coop. A box 2.5' high would, of course, double the cubic feet enclosed.

    Steve
    edited to say: Oops, writing at the same time you were editing, so I see that you do want square inch ventilation info. I'll search around a little for something . . .
     
    Last edited: Aug 9, 2008
  3. digitS'

    digitS' Chillin' With My Peeps

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    Quote:The only thing I find on the 'net is advice for dairy farmers . They suggest that one square inch of ventilation should be provided for every one square foot of ceiling area. They also pointed out that a 1,000 pound cow produces the same amount of heat as a 1,000 watt heater! My guess is that 1,000 pounds of chickens would produce more than that!!

    Your coop doesn't have a ceiling and attic space would be hotter than floor space usually but I think it would be better to have more than less hot weather ventilation for chickens. So, maybe that formula works: 1 sq in vent/1 sq ft coop. And, 17.5 square inches in vents for your coop certainly doesn't sound excessive to me.

    This also bumps up your post so that if others remember a formula on BYC they can respond.

    Steve
     
    Last edited: Aug 10, 2008
  4. patandchickens

    patandchickens Flock Mistress

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    I have 2 (but it used to be 3) ISA Brown hens in a tractor, the 'house' of which is 2.5x4 and 3-3.5' high. This is about the same # cubic feet per hen as your design has.

    Mine has approximately 2.5 square feet of vent area, NOT counting the pophole door when it's open. On cool spring or fall nights, with the vents shut about halfway, it gets rather damp in there and I would most certainly never consider having less ventilation. With the vents fully open in the summer, it is quite adequate and airy (dry/cool/unstinky).

    I do not overwinter the chickens in the tractor and I think it would be quite challenging to do so in a cold climate and have the chickens stay happy and healthy (for sure I'd be plastic-wrapping the run if I wanted to try that)

    There is no such thing as "too much vent area" provided that it can be closed down as needed according to conditions, so I'd build more rather than less. Make sure some of it can provide a crossbreeze at the end of the coop *opposite* where the roost is, for colder-weather times.

    You may need a hood or even a more extensive, engineered system to condition or somewhat pre-warm the air before it enters the coop, if you want to try using this coop overwinter in an area that gets Real Winter (sorry, I can never keep straight where everyone lives -- VA, is it?)

    Good luck,

    Pat
     

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