Warm/cool, humid/dry... mold question

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by Nugget, Nov 18, 2008.

  1. Nugget

    Nugget Songster

    Sep 2, 2007
    Hi all, I've gotten some great advice in the past about some mold issues in my coop. Tonight as I was leaving them some rice and spinach I couldn't decide whether to close them up (window and hatch) or not.

    I have an insulated coop (8x6 foot). There is a bathroom fan running all the time. There is a window (too small) and a hatch door to a completely caged in run (raccoon secure).

    Last fall and winter I had 9 sub-adults (male and female) with no mold problems at all. Some were rehomed, more bought and now we have 8 laying hens. This summer was really humid and we had our first mold problems.

    I added another small fan to circulate air around inside the coop and made sure I left the window and hatch door open all the time. Cleaned out all the shavings and washed the walls down with bleach. Not enough, more mold. I put in a 100 watt light to warm it up a little. We had mild improvement, then weather cooled and we had no trouble for about a month or so.

    I went out yesterday to the worst mold yet. We had some rain (fairly heavy rain) and my hens are doofuses who don't seem to notice rain. They came back in teh coop day after day soaking wet. I again bleached the coop all out, fluffed the wood chips and ensured nothing was wet. I just put in a droppings board... might this contribute to moisture since it's not absorbing into the wood chips?

    We're nearing our first snow and nights are around freezing. I read some info describing summer mold as being due to insuffucient ventilation, and winter mold being due to daughts (too much ventilation). I remember walking into a fish store in February. Walking into the hot humid store and bringing in all that cold dry air caused thick fog in the entrance, dripping from the roof.

    I'm wondering if I should close up the window and hatch when it's cooler outside than inside the coop, and opening as many vents as I can when it's warm outside. I turned on their heat lamp hoping that the heat, the ceiling fan and the small circulating fan will keep the moisture better controlled inside (I read something about moving air and heat compensating for a considerable amount of humidity).

    We're probably going to start cutting holes in it next spring but didn't think we needed to this winter. To sum up, the root of what I'm asking is, when it's near freezing, do I keep vents open, or close them up?

    Sorry this is so long... it seems kind of complicated to me and I've been thinking about it a lot.

  2. WoodlandWoman

    WoodlandWoman Crowing

    May 8, 2007
    If you're having mold problems, then I would say you need more ventilation. I remember reading your earlier mold problem thread. Your coop is beautiful, by the way. Really lovely. As I recall, other than the fan you installed, your coop doesn't have any actual vents, does it? You only get fresh air moving through your coop if you have a door or window open?

    I would really look at adding vents around the peak of the roof, so air can naturally move up and out. Right now, with nothing open, even your fan is going to have a harder time pulling in fresh air. It has to come from someplace. Even small vents would really help.

    I think adding vents above the level that your chickens are roosting, will simplify your life a great deal. If you leave your window open, how does the airflow interact with where your chickens are roosting? Will they be in a draft? In cold weather, that would be a problem. That's why vents above the roosting level are nice. If they'd be in a draft with the window open and you don't want to add vents right now, then I'd look at adding a wind break inside the coop, for the roosting area. Basically just a more sheltered area for the roost. Or you could move the roost. Let us know if you think a draft is going to be a problem, ok?

    I'm sorry you are having more problems. I know you love yor chickens. [​IMG]
  3. I agree about the vents.
    Plus, I suspect what you are enduring is what we have and- an unusually wet spring summer and fall. Look on it as a test of your facility under the worst conditions, and once you solve the problem it's unlikely to recur.
  4. Nugget

    Nugget Songster

    Sep 2, 2007
    Thanks for your help Woodland Woman and Lynn

    There is a 1 foot square window and a hatch door about the same size, and a ceiling vented bathroom fan blowing coop air out a chimney. Added to that is a little oscillating fan to help improve air movement inside. I just recalled that I did in fact close up the coop a couple of times before this last mold problem thinking it was too cold at night and that 'mold season' was passed. Obviously not! The chickens might be in the line of draughts when it gets cold out but I am not sure how I would address that... I'll have to see what happens when it gets cooler, and hopefully drier out. It sure has been a wet year Lynn! NS is becoming a rain forest [​IMG]

    Do you keep the same kind of ventilation through the winter (february) as you do in the summer in your coops? We will be adding more vents for sure
  5. GallowayFarms

    GallowayFarms Songster

    May 19, 2008
    Ok. From your account it sounds like the humidity outside the coop is just as high as inside the coop.

    You might need to get a dehumidifier. Or if the inside of your coop isn't painted you should which will help with stopping the mold. It grows into the wood so even if you bleech the top layer of mold off the spores are still down in the grain of the wood. I would paint the inside with a good primer then find a good mold resistant paint.

    You should get a hygrometer( tells you the humidity) to find out what is really going on before you cut your coop all up. Bc if the humidity outside is just as high as inside the coop ventilation won't help a bit.

    Just my two cents I hope this helps.


  6. WoodlandWoman

    WoodlandWoman Crowing

    May 8, 2007
    Our coop has 3 smaller windows at one end and 2 that are huge, taking up a large portion of the wall they're on, at the other end. I went out and measured them for another post one time, but I don't remember which one. [​IMG]

    Our highs in the worst of summer are the upper 90s, with humidities in the 90s, too. When it's really hot, all the windows in the coop are wide open, to keep it from being like an oven in there. Even though the air feels thick, we haven't had a mold problem in the coop. We do need to run a dehumidifier in the basement of the house during the summer, though. That's pretty common here.

    Spring and fall, we adjust what windows we have open, depending on the weather.

    In the winter, the windows are all closed, but there's still a small amount of venting. I think the coldest it's gotten here is a low of -30 degrees, but usually -20 is the lowest it gets. Mid-winter the air is very dry here, due to the cold. Early and late winter, when it's not as cold, the air is more moist. I'm not sure how the humidity here compares with your area, at that time of year. Anyway, that's what we do.
  7. patandchickens

    patandchickens Flock Mistress

    Apr 20, 2007
    Ontario, Canada
    Normally I'd suggest that the ultimate solution is likely to involve more ventilation... BUT, that will not always completely solve the problem in cases where the outdoor air is just as humid as the indoor air [​IMG] and I know that does happen for prolonged periods in some climates.

    I will still suggest more ventilation [​IMG]

    But at the same time, I wonder if the problem is maybe not just the current conditions but having perhaps a well-entrenched mold infestation from before? If so, you may have a lot of trouble beating it unless you bleach regularly (in ALL the nooks and crannies too, and then dry it out real well) and/or clean all surfaces and give 'em a couple coats of a paint that contains a mildewcide (ask the paint guys for it).

    A droppings board is unlikely IMO to be adding to humidity -- while shavings may absorb some moisture from poo that falls directly onto them instead of onto a board, that moisture remains available for evaporation into the air, as opposed to most of it being removed entirely in the morning as happens with a droppings board). You can sprinkle some shavings (used,from the floor) on the droppingsboard though if it makes you feel better; if nothing else it makes the poo easier to scrape off [​IMG] Some of the shavings will get blown off by flappy wings so don't put 'em on *too* thin.

    Good luck,

    Last edited: Nov 19, 2008
  8. Dustoff79

    Dustoff79 Songster

    Aug 5, 2008
    San Antonio, Texas

    We're probably going to start cutting holes in it next spring but didn't think we needed to this winter. To sum up, the root of what I'm asking is, when it's near freezing, do I keep vents open, or close them up?

    open the vents, use some heat and keep up the air circulation. yes the heat and air circulation help because warm air holds more moisture and the circulation distributes the air to keep the saturated stagnent air from remaining in one area. The ventilation helps pull fresh and (tho it does not sound like it) less humid air from the outside in, and that less humid air will pick up some moisture and with the ventilation it is removed outside. If the outside temp is lower than inside even if it is 80% humidity outside, that cold moist air when it warms up will still be able to suck up more moisture.

    I agree with Pat on the ventilation, and to clean the walls/floors.

    do the best you can for now, ventilation and clean the area with a weak clorox solution or a product called SPORICLEAN. http://www.killmoldfast.com/ It is darn near impossible to get all the mold as it gets into the wood, but If you can get some Sporiclean it really works well, use it on all your surfaces, there will be mold spores everywhere, and when the weather warms up, clean it again then when it is good and dry, paint with a mildew killing primer like Sherwin-Williams A-100 Exterior Primer and top with a good paint.​
  9. orchidchick

    orchidchick Songster

    Mar 23, 2008
    south florida
    You may find the addition of Stall-Dry helpful to aid in the further reduction of the overall moisture in the coop itself. Just one more thing that may be of help. I find it really effective in the sweltering humidity of our Florida summer storms.


  10. It was a rain forest until last night!

    Yep, we'll all in deep snow





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