How do i know if i have enough ventilation?

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by babsh, Nov 11, 2008.

  1. babsh

    babsh Chillin' With My Peeps

    Apr 30, 2008
    We converted part of our shed for a coop. It is 4.5' x 7'. I have two 18x24" windows. We just transitioned the girls a couple of days ago. What i'm trying to figure out is how much i should leave the windows open for proper ventilation. The first night or two i had them cracked just a bit and there was condensation on the windows. Clearly not enough. So I opened them more the last two nights and have not had any condensation. However, we put an outdoor thermometer in there with a humidity gauge and it shows 95%. I have no clue what it should read. After all, it is sleeting here right now. And, i'm not really sure how accurate it is.

    So is there some kind of formula? Also, i'm really trying to wrap my head around the idea of leaving windows open when it's 18 degrees outside.


    Barb in Minnesota
  2. dftkarin

    dftkarin Chillin' With My Peeps

    Jun 27, 2008
    I have the same issue. I just moved my 4 hens into a 3'x5'x4' high coop with 2 big windows, 2 smaller windows and a lot of cracks between the walls and roof. It is getting into the 30s at night and last night I left only one of the small windows open and there was no condensation or even any feel of warmth in the coop when I checked on them in the morning. Shouldn't the inside of the coop have felt at least a little warmer? Now I'm wondering if all the cracks around the window flaps and doors and roof are enough ventilation on cold nights and maybe I should close everything up?

    Has anyone ever made a 'coop-within-a-coop' - a cozy semi-enclosed area inside a coop to make it easier for the hens to generate and keep warmth close to them?
  3. WestKnollAmy

    WestKnollAmy The Crazy Chicken Lady

    Apr 22, 2008
    upstate SC
    Well, maybe a little more information would help.
    Is it insulated?
    I don't like birds kept in a room without any type of air movement through it but I can see your predicament. I would close the windows down more and find another way to ventilate. Chickens throw off a lot of moisture so they do need it not too stuffy but with it sleeting (lucky thing! I'm sitting here in shorts!) I wouldn't want it too get too cold for them either.
    There is a great article somewhere on someone's page here on BYC. Do a search for ventilation or maybe someone will chime in with the page where it can be found.
    Sorry I can't help more. My coops only have 3 sides enclosed with wire on the south side. The most we get is a bit of rain, if we are lucky.
  4. Heather J

    Heather J Chillin' With My Peeps

    May 29, 2008
    I built my coop with lots of windows, a roof vent and some additional rafter vents, but since I have young ones in there, I close all the windows up at night so it'll stay a bit warmer, then open up windows depending on the outside temps and weather. The roof vent and rafter vents help keep things under control for the few hours the windows are all closed. They're all feather-foot birds, it's been rainy, and their run isn't finished yet (heck, the inside of the coop isn't finished yet, I have old pallets screwed together acting as internal walls while I build the individual pens), so the pop door isn't open too much yet. I'm definitely going to try and convince dh we have to cover their run for winter, then i can let them out more even in non-gorgeous weather. Maybe I'm wrong, but until the weather gets better in the spring, i plan to continue closing all the windows at night to allow the coop to hold heat better.
  5. patandchickens

    patandchickens Flock Mistress

    Apr 20, 2007
    Ontario, Canada
    Condensation on the windows is not necessarily proof of insufficient ventilation -- remember the window glass is getting pretty cold, so can condense moisture out of air that is substantially less than 99% humidity.

    I'd say the most fundamental test of sufficient ventilation -- that is, the thing that tells you whether you have REALLY INSUFFICIENT ventilation -- is, when you go out to the coop in the morning and put your nose down at 'chicken level', do you smell a whiff of ammonia (or worse, knock-yer-socks-off ammonia)? Enough ammonia for the human nose to detect is enough ammonia to harm the respiratory tract (bird and human alike) and tells you you *really* need more ventilation.

    Beyond that, I'd say it depends on multiple indicators of coop humidity. Things like, do you see condensate on walls or on an insulated ceiling; do you get frost forming near any drafts; is there mildew growing in corners etc; does poo in the litter stay somewhat moist instead of drying out; that sort of thing. Hygrometers (humidity meters) are ok too of course if calibrated correctly but the cheap ones are often off by a LOT, in my experience.

    You will probably just have to fool around with it somewhat til you have enough experience with how your coop behaves in different weather. I know that's inexact, but, hey [​IMG]

    Good luck,

  6. babsh

    babsh Chillin' With My Peeps

    Apr 30, 2008
    Hmmm. I hadn't thought about the window condensation not necessarily meaning too much moisture. Good point. I will try the smell test and see how it goes. So far, I'd say it smells like poop, but not ammonia-y. But I haven't smelled it at chicken level, so I will try that and play around with the windows a bit.

    I will also watch for condensation on the walls and ceiling.

    Thanks for the replies.


    p.s. Yes, it is insulated, btw. I should have a heater arriving soon from and i think I will not feel so worried about having some windows cracked when i know they are at least above freezing.
  7. ROC4K

    ROC4K Chillin' With My Peeps

    Oct 21, 2008
    NE Wisconsin
    You can salt test your hygrometer in a ziploc bag with moistened table salt in a bottle cap at room temp. after 8 hours you should read 75%rh. adjust if needed and retest. If you can't adjust the unit + or - the amount your unit is off from the control test reading for your accurate...or more accurate reading.
  8. vermontgal

    vermontgal Chillin' With My Peeps

    Ok, So if you have a hygrometer (accurate) in a coop - what % humidity should it stay below?

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