Needing input on vent/window situation

[LedgeWoods]

My coop is the south end of our pole building...measures 7'x16' for 41 hens. There are 4 insulated south-facing windows, entry door on the west and wall fan-vent on the east side that stays on (draws out the air) 24/7. Up until this point, the night-time routine is to leave 2 of the windows cracked (about an inch) with the vent running. Once freezing temperatures set in, is it going to be OK to leave that fan vent running or should it be turned off with windows left cracked for ventilation??

I'll get a picture posted soon...
Thanks!

 

[Judy]

I'd say you will have to judge the conditions in your coop for yourself. You should be able to achieve adequate ventilation without a fan, but 1" in two windows does not sound like enough.

 

[Bear Foot Farm]

I'd just open the windows and forget about running the fan at all unless it was above 80 degrees.

Once it gets around freezing, just leave one partially open and see how it goes.

 

[Mac in Wisco]

Quote:
I'm confused. Is the exhaust fan pulling air from the whole pole barn or just the chicken coop section? What is the air quality in the coop without power ventilation? How warm does it get without power ventilation?

I have a layer barn with a few thousand hens. They do require power ventilation to remove moisture/ammonia/carbon dioxide/excess heat in the winter when the barn is mostly closed up. I have one small fan that runs continuously, and several others that are set on thermostats. As the barn gets too warm, more fans come on. As it cools off, the extra fans shut off.

The one small fan does a good job until the temperature gets down in the single digits and then the barn is over-ventilated, it gets too cold and too dry and dusty. Last winter I put a percentage timer on that fan that allows me to set the amount of on and time in each five minute period. I can adjust it to run, say, two, three or four minutes out of every five. I adjust it to keep the relative humidity in the barn around 70 to 80 percent. This keeps the dust levels down and the temperature up.

Your ventilation needs are going to change with the outdoor air temperature. Ventilation is mostly required to removed excess moisture from the coop, but as the outside air temperature drops, the amount of air required to remove that moisture becomes less and less. You may find that once it gets too cold outside that the ventilation needed to remove that moisture can be provided by natural ventilation, provided that there aren't other air quality issues. Only you are going to be able to tell what is appropriate, given the amount of moisture in the coop and how much air your exhaust fan moves.

 

[crazeetxn]

https://www.backyardchickens.com/web/viewblog.php?id=1642-VENTILATION!

This link helped me out when I was doing mine. I only have 10 chicks for out 12x12. May help you get down the road...

 

[LedgeWoods]

The part of the pole building facing us with the 4 windows is the coop. It's the 7x16" end portion of the building. The 9" fan vent is only for the coop. I might add that it is fully insulated & I have sand over cement for bedding/flooring. Last night we were down to 37 degrees & the coop thermometer read 48...so it seems they are doing a good job generating heat. I may play around with leaving the vent off overnight with the windows cracked open and see what the morning brings before any bitter cold arrives.
Thanks for the replies!

 

[Mac in Wisco]

Very nice. Where are you at in Wisconsin? I am just south of La Crosse.

Don't worry too much about the temperature. Ventilation is needed to remove moisture from the coop even if it means sacrificing the heat. You're better off shooting for a given humidity level, either by measurement or observation. If things are getting too dry and dusty in the coop you need less ventilation, if the condensation is rolling off the windows in the middle of winter like somebody hit them with a garden hose and the litter is too damp and blowing off ammonia, then obviously you need more ventilation.

For what it's worth (it needn't be this complicated), I like to play with the numbers and look at the engineering side of things. I've studied this extensively and one can calculate the proper amount of ventilation required. For each bird you probably have 5 to 6 ounces of water entering the coop each day and about 1 oz per bird leaving in the form of an egg. The rest needs to be removed by the ventilation system. The engineers will tell you that the minimum ventilation required for birds at around 70 to 80 degrees is 10 cfm per bird or higher. The minimum ventilation required for very low temperatures (say, -20 F) is just under 1 cfm per bird, which I've found to be quite true with our layer barn of 2500 birds. Last winter in the coldest of temperatures I was throttling the ventilation back to around 2500 cfm on the coldest of nights and it would keep the relative humidity in the barn around 75%.

A 9 inch fan sounds about the right size size for your setup. I'd guess it moves 400-500 cfm of air. Which would keep the coop well ventilated in moderate temperatures, but as the temps drop you'll need less and less ventilation to remove that moisture and it will probably be moving too much air as the temps drop down below freezing or lower.