Venting my barn coop - questions

[mlorne]

Hello all,

I have been reading alot about venting lately and I have a couple of questions regarding my barn coop. My coop occupies a very small part of an old cattle barn. The exterior run is fully enclosed, while the interior coop is enclosed in wire and wood (i.e. not solid walls). The primary line of defence against coyotes and racoons is the barn structure itself. There are a number of windows, but none of these windows open. There are two working doors, but only one is used, with the other being shut for predator control. Here is a photo of the barn:



Inside of the barn, with it's thick concrete walls and ten or so feet of insulating hay above, the temperature is consistently 10-20 degrees cooler in the summer, and 5-15 degrees warmer in the winter. For this reason, I have resisted letting too much air into the barn. The lower level is very open, with plenty of fences and feeders, but very little in the way of seperating walls.

So, with such a large, open, albeit enclosed, space (approx. 2500 sq.ft.), is ventilation such an issue for me?

I appreciate the help,
Michael

 

[joebryant]

I know the answer to your question, but I'm so darn jealous of your having that barn that I don't want to talk to you.

 

[booker81]

Quote:
ROFLMAO!

I think that if it's nicely temp controlled, the humidity isn't bad in winter, and it passes the smell test, you should be good.

I too am a bit jealous

 

[teach1rusl]

Unless you're keeping hundreds of chickens in there, I think you'll be safe

 

[cfdf]

I don't know about the ventilation in there but WOW!

You have me dreaming about all the chickens I could put in there....101..102....103...

 

[patandchickens]

If you will only have a relatively few chickens and the barn is DRY inside, you can do your ventilating mainly into the interior of the barn rather than the great outdoors. The more chickens you have in your coop area, the more venting to/from the indoor barn air you will need.

The difficulty comes if-and-when either a) your chicken population exceeds what that will take care of year-round, and/or b) the barn is not always really all that dry. For instance if there is water seeping in from leaks or from rising groundwater or from busted or missing gutters/downspouts or cattle-related phenomena; or (this is a biggie) from condensation on the first really warm days/weeks of late winter, when the concrete barn structure is still cooooolllllld and humid warm air drifts in and condenses out and it gets real clammy in there. When that happens it can create problems with mold, and if it persists into the next cold snap it can also create problems with frostbite.

My best suggestion for people with this type setup (coop inside a very very large-thermal-mass building) is to have ample facilities for dealing with BOTH situations -- the ability to close off outdoor coop openings (except popdoor obviously) and have quite a lot of indoor airflow going on, AND the ability to close off the indoor ventilation and have considerable *outdoor* air exchange as needed. Sometimes you can get away with merely closing off nearly all ventilation, til the brief unseasonable warmth is gone, especially if you have fairly few chickens in a fairly large coop space. But this will not always work, esp. if the barn has any of the other abovementioned tendencies to acquire moisture as well. So you will have to 'play it by ear'.

I am *totally* not trying to discourage you, it's a great setup for a coop provided you predatorproof and ratproof it well, just saying that it will soemteimes have to be managed a bit differently than the usual backyard coops discussed on this site.

Good luck, have fun,

Pat

 

[mlorne]

Thank you everyone for your replies. While the space is large and could hold probably 300-400 chickens, that is simply not in the cards

Pat - I was hoping very much that you would reply, as you seem to be the de facto expert on ventilation. Indeed, most of my ventilation concerns came after reading your posts. The interior space is not, at this point, sealable, as you can see here:



The bottom half of the coop is effectively wooden fencing, while the top part is just hardware cloth. As a result, the coop is essentially an 'open air' coop to the rest of the barn.

The main door of the barn has a 'window' without glass that is currently covered with plywood. I could easily cover this with hardware cloth for ventilation into the barn as a whole. The opening measures perhaps 30"x30". Furthermore, I can make a similar opening in another door on the other side of the coop. This would allow for fresh air into the barn when open, or closed up during colder winter days.

I have noticed that the air in the barn, while much cooler, seems 'heavier' than the outdoor air, provided there is air movement outside. Perhaps I will bring a moisutre guage down and see if I can establish a baseline.

My question would be thus: what differential between outdoor humidity and indoor humidity would be ideal? Is a 1:1 ratio ok, or should I be aiming for a 80% reduction if possible?

Thanks everyone,
Michael

 

[patandchickens]

It's not really a matter of aiming for a particular difference in humidities or temperatures... it is just that you do not want your indoor humidity to go over 70%(ish) if you can help it. Most of the time it *won't*, unless your barn has other problems -- the only time there will be a question is on those late-winter and early-spring days when the concrete etc of the barn is still real cold and warm humid air comes in. Some barns get real, real wet (like condensation forming on all surfaces!) in that weather, some are essentially-unaffected, and most are somewhere in between.

I would suggest that as long as your barn does not have any KNOWN moisture issues (leaks, rising groundwater, or lotsa cow humidity during wintertime) then you should be "basically fine", and can probably afford to just roll along without modifications and see what happens. By next April or so, you will have discovered whether any alterations (in structure or in management) will be necessary for future.

You *could* put a hygrometer (humidity meter) out there, but I am not sure how worth it it is, because they are almost all of them *fiendishly* inaccurate and unreliable, and really you seldom need numbers per se. What you need to know is, is there mold or any trace of condensation/frost forming anywhere in there. If there is, humidity is too high. If not (especially, in the winter, if you are not getting condensation/frost) then that pretty close to 'proves' that your humidity is not excessive.

(e.t.a - if you do not have other livestock in the barn at this time, be aware of the potential for rat problems. Keep a sharp eye out and you may need to consider both fine-tuning your feeder arrangements AND rat control measures)

Good luck, have fun,

Pat