One more ventilation question. How much humidity is too much?

[Linn Bee]

Hum-m-m-m. I don't know if I've ever seen what level of humidity was safe. I would take out my humidity gauge out to the coop, but aside from the true moisture level I don't know what I'd learn. Guess I'll ask the old timers where the humidity should be.

Okay! How much humidity is too much? I know the ratio of bird to vent. I don't know what level of humidity would be dangerous at what temperature. Is there a 'magic number' for humidity or is it just add more ventilation?

Love, Linn B (aka Smart Red) Gardening zone 5a - 4b in south-est, central-est Wisconsin

 

[Wynette]

In my opinion, and I'm no expert, the more ventilation, the better. THe damper it is, the more likely of respiratory issues cropping up. I had chronic sneezing the first year I had chickens in one coop. The more I researched on it, the conclusion I came to was that it was too tight - not enough ventilation. I began only latching the bottom of 3 latches that hold the door tightly closed, so the door gaps open at the top. A month after doing this, I noticed NO sneezing going on. Since then (that was several years ago), I never latch the door completely, and have had no further issues.

 

[Fred's Hens]

In the winter time, the cold air simply is drier. Cold air cannot hold as much humidity as warm air can. Our relative humidity drops down to 25% ambient here, with regularity in Dec-Feb. My guess is that once the air flow begins to come from Alberta, as it does in the upper midwest, in the winter, your's will be quite similar.

Thus, the object is to match the outside. If the outside is 25-50% RH, that's your goal. If your coop is 20%-40% more humid than the outside air, it is because there is trapping of poop moisture and bird exhalation moisture. That is the focus. Keep the inside as "dry" relatively speaking, as the outside air. If the humidity rises inside the coop, for the reasons given, in the same temperature as the ambient temps, then plain and simple, there must be frost, condensation and the issues that create havoc.

 

[elmo]

Fred's Hens :

Thus, the object is to match the outside.

x2.​

 

[kelidei]

This is my third winter with poultry. I use deep litter in all 4 coops. In the winter I add PDZ to the shavings whenever I add more... which is usually every 4-5 weeks. We also added more ventilation just below the eaves. I leave the windows open about 2 inches. I also have radiant panel heaters over the roosts (they are safer and provide a place for the birds to warm up) and I think that helps too. I used to be too afraid the birds would freeze... now I realize too much moisture is worse than the cold.... so vents and windows remain open even when temps are below zero. In fact with my turkey coop I leave one door open all the time (and they still prefer to sleep up in the rafters of their pen in the cold)

This seems to be working... last winter I had very little condensation and the litter had just enough moisture to continue to compost. Oh.... We also put insulation and a moisture barrier on the ceilings... Also no open waterers in the coops that will evaporate...

 

[kittycooks]

I agree with all of the above about lots of ventilation. There is no magic number because humidity levels change depending on the temps and outside weather conditions. If it is raining it will obviously be more humid than below freezing temps, and summer has more humidity than winter. I simply add more ventilation if I see frost building up inside the coop during the winter.
The first year I had chickens they pecked holes in the plastic run and I was worried they would be chilled, but by mid-winter I noticed the coop and sand floor stayed dry, there was little to no frost build up and the chickens were fine.