Wet Coop bedding

[mobius]

OK. Let's see if anyone agrees. I would consider the followng to start with:

1. Open the 2x2 door to the upper story and leave that gable end window open all the time.

2. Under the eaves, remove any wood soffit and replace with hardware cloth. Assuming it is open to the coop.

3. Add a large maybe 2-3 foot square or round vent in the other gable end. Cross-draft. Hardware cloth over all openings from inside or outside, depending on how you open things.

How many chickens? They do add moisture overnight. Pop door open overnight?

It is a LOVELY coop and run. Now the tweaks.

OP, I hope this is okay with you!

 

[mobius]

Here's my coop. Let's cut away! Today I had both front doors open as well as both windows on the E and W sides.


This is the south side


North side on the right, east side on the left with the window. Today the window was open all the way. The 2nd story is fully separated from the 1st story except for a 2'x2' access hatch which is kept closed.

As of 9pm, it is 29 out, humidity is 89%. Inside of the coop is 35 with 83% humidity. I closed the front doors at 8pm tonight. Both windows are open 25% right now. I gauge the moisture in the coop by the non-working windows in the front doors. If they frost up on the inside, too much moisture. If they are frost free (or condensation free) I am good. The coop is 2x4 construction with standard fiberglass insulation. Floor is concrete and ceiling is 2x6 rafters with insulation.

When you say inside 35 with 83% RH we are finding this possibly to be the "danger zone" for chickens if it drops below 32F at night...just saying...humidity seems to be higher around freezing temps..time to open everything up...

 

[Howard E]

Hello, this is my first time posting. I am a new chicken mom. I am trying to solve our chicken coop mystery. Our chickens have a large 12x18 outdoor run that has natural cover from trees and a small (kit from tractor supply) coop with nest boxes. Our birds are a mixed flock - 2 orpingtons that we purchased as laying hens, and 2 (2 roosters and a hen) that were hatched out at my school ( I am a teacher) that are meat birds. They have free access to the pen and coop all day, but they put themselves to bed at dusk. Their food and water are outside. The coop has spots for 2 low roosts, but the meat chickens cannot use them and typically knock them over.

Sorry for the novel length description, but the problem we have right now is that the coop bedding (pine shavings and hay in the nest boxes) is getting increasingly damp. We live in the Carolina's and have humid weather all year round. Our bedding system worked GREAT in the summer and we hand little smell and nice clean birds. Now that winter has arrived, it does not seem to be drying and I am now bedding a shallow layer and cleaning everyday and it is still smellier than I would like. My meat birds also have dirty breast and belly feathers.

What am I doing wrong?
Help from a chicken newbie in NC

What size is this TSC coop? Most likely it is too small for 5? adult birds. You've had these meat birds since last summer and still have them? Any plans for a plucking party? If you started them last summer, they were smaller poults back then but they are adults now and all are dropping considerable adult sized loads each and every night, and in winter the nights are long. Meat birds of the Cornish type may be OK with simply resting on the bottom of the coop in their own filth, which is why they would be dirty. Moisture comes from the breath and the droppings of them all, and in a tight coop, will accumulate, condense and make things wet as well as cause health issues for them all, and not just from the filth of the droppings. Google "roup in chickens".

Sounds like it might be time to thin (and eat) 3/5 of the herd!

 

[Howard E]

Thomas: As I recall, you keep something like 24 or so layers in there? If so, that is a pretty big moisture load to deal with. Once you insulate and go with anything but wide open (as with the Woods houses), getting the ventilation right for that many birds is a seriously tricky business.

The insulation allows the heat from the birds (and any solar gain from sunshine streaming in during the day) to heat things up inside relative to the outside, which causes evaporation of any condensation on the interior surfaces and in the litter. That is the good news and the good part. But to escape, the moisture laden air has to have a place to go. So it is a balancing act to get the moist air leaving and make up air coming in at such a rate it is venting moisture to the outside yet still retaining enough heat to dry things out. Goal in winter would be to elevate interior temps by 10 to 20 degrees over exterior temps, which should help dry things out. In the summer, they would be left WIDE open. Again, source of heat is the birds themselves (all of them little moisture emitting radiant heaters) and any solar gain you can find.

Without changing the aesthetics much, you may be able to install some modest sized rectangular shaped gable vents high up in the wall between the house and run. Nobody would see them and the outside would appear as it does now. With gable vents opening to the run, you should not get any snow or rain coming in. Rule of thumb for ventilation is 1 sf of ventilation per 10 sf of floor space or by extension, about 1/2 sf of ventilation per bird.

Lastly, did you use a vapor barrier between the interior plywood wall and insulation? If not, there is a good chance you are also getting condensation deep within the wall. Without a vapor barrier, moisture vapor enters the wall cavity, then passes through the insulation until it hits the cold exterior wall where it condenses into liquid moisture. The insulation gets wet and stops insulating, water condenses on the exterior wall and will run down the wall to the sills, which if not made of treated lumber, will rot out. Plus the usual suspects of mold inside the wall cavity.

As they say, seriously tricky business.

 

[thomasboyle]

Thanks for the suggestions. As of 1pm, humidity in the coop is at 71% now and temp inside is 31. It is 26 outside with 79% humidity. Some snow expected tonight. Gotta love remote weather stations that you can check online and on your phone!

What I don't understand is how more ventilation will lower the humidity in the coop when the humidity outside the coop is higher. Its been a while since I have been in school, but according to the laws of thermodynamics, if I ventilate a room at 73% humidity with the outside air at 79% humidity, my room will soon be equal with the outside at 79% humidity! If the outside humidity is lower, then obviously more ventilation would improve the room's humidity. It would seem to me the only way to lower the humidity when the outside humidity is higher would be some sort of mechanical ventilation - heat or dehumidifier.

I can open the 2'x2' door between the first and second floors, that is easy. The roof overhand has solid wood soffits, so no ventilation except the triangular vents at the very peak of the roof, one both sides. I could look at adding soffit vents, but this would be a summer project! This would give additional venting to the attic section, not the main coop section. I could also enlarge the vents at the roof peaks.

I have 13 chickens right now along with 7 pekins and 8 mallards. Pekins have their own section within the coop, mallards are in with the chickens with the chickens on roosts 3' off the ground and ducks on the ground below them. Miraculously the ducks do not get poop bombed from above! I have 2 pop doors, one for the chickens, one for the Pekins, and they are closed at night.

There is a window one the wall between the shed and the run, and that is always 50% open in winter, 100% in summer. It is 30" x 48", same size as the window on the east side which is visible in the pics. I did not build the shed, it was built by the previous owner a few years before I was born, so it is approaching 50 years old. They did use clear plastic sheeting between the pink insulation and the interior wall. My sill plates are starting to fall apart.

One of my project either this summer or next will be to remove the run from the shed, and attach the run to the back of the big barn (40x50). I am in the process of replacing the barn siding with new wood. The chicken will get moved to a larger space in the main barn and the old shed will be torn down. My chickens have survived 4 winters in the current shed, I guess I just never knew the humidity inside until I bought the Acu-rite remote sensors a couple months ago!

Here's the big barn I am currently renovating. It was built in the 1800's, post and beam construction with chestnut beams and wooden pegs holding the beams together. The chickens and ducks will be in the little door on the far right. The room in that section is about 15x25 and has 8' walls but is open all the way to the roof. I am guessing I won't have a moisture issue with the big barn as it is nowhere near as air tight as the shed, and the volume is 25,000 cu ft compared to the shed at 2,300 cu ft.

 

[mobius]

@thomasboyle Whew nice post, lotta info! I know, right? I got super-confused (and concerned about birds) which prompted me to start measuring.

Otherwise i would be in the dark!

I will start with two findings:

1. Without poultry in my coop the temp and humidity tend to nearly equalize in about 2-3 hours. It may be 2F degrees warmer inside, slightly less humidity.

2. With poultry in the coop, they raise the temp in my case from 10 to 15F in two to three hours. The humidity drops a great deal...last overnight it was 25% lower humidity.

Folks seem to agree that PROPER ventilation allows the heat generated by the birds to reduce humidity. Otherwise, where is that wet air ( equalized to outside from the day when birds are out, AND and including then MORE wet air from birds' respiration inside overnight) going to go when they increase the heat? Just saying. The venting takes the wet air out as heat rises and the venting then pulls out the moisture...anyone can add to this theory, BTW.

We want the house to DRAW...think cross-ventilation. I have this kind of ventilation in my home and there is no airco in the summer...none needed. I open a skylight and a few lower windows and whoosh!

So thermodynamics have to take into account not just RH but temperature shifts, air flow etc.

Now. You have measuring devices. Consider doing as I am. Tweak the ventilation you have. For example, leave pop door open. Open windows fully. Open that 2x2 ceiling opening. Vary it. Measure. Record. I bet you can get that moisture down. Look at my thread. I know there is a lot of info there...and my setup is different from yours. But it CAN be done. Check your lovely deep litter and make sure it isn't TOO wet. @Beekissed has great info on that. Get the birds to mix it up for you! Scratch before bedtime!

Wish I had those barns...peg construction? Nice. I have barn envy.

 

[moukoyui]

Wow, your coop is SO much nicer than mine!!

Here is a link to our coop. https://drive.google.com/open?id=1tU7_aT3iYpD1fl18UYFhQmNwpDQT9FNNUQ

It was sold to us for up to 6 birds. It is always open to the run each night and has full length portions of mesh in the front and back. We have only closed the coop up due to weather 3 or 4 times this winter and that was only over night. They have 24/7 access to the outdoor part of their home which is a 12 foot by 16 foot pen. I am starting to really worry that is a size issue. Our little "school" chickens are already mush bigger than our 3 year old Orpingtons. Eventually we may expand the chicken area into our hay shed next door, by means of a chicken tunnel. This would give us the space to create a more "normal" coop.

I really do want want to kill and eat my "school" birds as they are SO friendly. My favorite rooster will let me hold him and seems to really like getting his head and neck scratched. I currently clean the pen weekly as, it is not deep enough for a deep litter method of keeping chickens.

 

[Howard E]

Do a Google search for "reducing condensation in buildings" and some nearly universal causes and solutions will materialize. This is one example, but the Internet has tons of information just like it:

https://www.designingbuildings.co.uk/wiki/Condensation_in_buildings

Bottom line is they will all say to reduce moisture in the buildings, solution is to a), reduce moisture generated in the building, b) provide heat to allow air to hold more moisture, which is felt as a lower relative humidity and c), increase ventilation to move moisture laden air to the outside.

Most of us see this all the time in our bathrooms. Take a long hot shower with the door closed and the vent fan off and you will step out into a warm, sauna like room, with moisture condensing on everything in sight. Mirrors fogged up, windows fogged up, and just about anything metal dripping wet. But turn off the hot water, open the door, turn on the vent fan or do both and all that will instantly go away. Temp will drop, but all the fog and condensation will go away and the room will start to dry out.

Basic condition is that in any building where air and moisture can move freely back and forth, such as an open sided shed, temp and relative humidity levels will tend to be the same, inside and out. Even closed up, the laws of physics suggest that pressure, heat and moisture levels will try to equalize, only slowed by any barriers that are in place (closed doors, closed windows, vapor barriers, insulation, etc). Managing the movement of heat and moisture is huge issue in virtually all buildings that make an attempt at some form of environmental control.

Think of a chicken house as being like a bathroom. Once we populate a building with birds, things are no longer the same inside and out. The birds themselves are the source of two things......heat and moisture, both of which are going to move to the outside.

So if we could just add heat from the birds or another source, the ability of the warmer air to hold more moisture goes up and the relative humidity level goes down, leading to evaporation of moisture from any wet surfaces. One free and easy way of doing this is in winter is to include lots of window space on south facing walls to allow sunshine to stream in resulting in heat gain from solar radiation. This even helps during the day when the birds are out and about and not in the building. If the house interior heats up any at all relative to the outside temps, it starts drying out. So windows not only add beneficial winter light, but also heat. But they need to face south into the winter sun to allow this to happen.

But in addition to the radiant heat given off by the birds, they also bring in moisture. From their breath, from their droppings and if we have waterers, etc. inside the coop, any spilt water has to evaporate. Also, if the coop has a dirt floor and moisture is being drawn up from the soil, that goes in the air too. These are all sources of water that if not vented, or if enough heat is not added to allow the air to hold it all, will build to the saturation point and start to condense out. In the extreme, moisture will condense on just about everything, including on the birds, will then evaporate from the heat generated by the birds, leading to that cooling effect. They are being chilled. This is really felt at night, when the air is cooling. The cooling effect, taken to the extreme is what causes frostbite. Do a google search on "causes of frostbite in chickens" and almost all of them will make some sort of reference to excessive moisture in the building, combined with zero or sub zero temps. So somewhere around 0F is where the bird's natural ability to ward off frostbite fails. A dry bird can go below that. A wet bird will likely suffer some damage.

So to house birds in zero to sub zero temps, without the need for supplemental heat, two things need to happen. Any heat from the birds and/or solar gain from sunshine streaming in through windows will lower the relative humidity level to help avoid condensation, but the moisture being generated by the birds and other sources is still building. If that moisture is not vented, as soon as the air cools just a little bit, humidity level goes to 100%, the dew point is hit and moisture starts to condense. Think wet bathroom. So there needs to be a controlled level of put and take. A controlled level of warm moist air moving out as it naturally wants to do and being replaced by cooler make up air, which when warmed just a little bit takes up the moisture being generated by the various sources found within the house. In short, a conveyor is setup moving the moisture out but at a controlled rate such that the heat level always stays above the outside temp. That elevated temp is the engine that runs the conveyor. A bathroom vent fan does about the same thing if you run it while taking a hot shower.

In cold climates, (my guess is this kicks in around Zone 6a), insulation is needed in the walls and roof to help hold in the radiant heat generated by the birds to get that 10 to 15 degree temp spike of inside air over that on the outside. Without insulation in sub zero weather, the bare walls will suck the radiant heat out and in turn, radiate it to the outside vs. convection of the warm moist air to the outside. In short, in Zone 5a and colder climates, insulation is likely needed to help keep the conveyor running. We are hearing reports of birds kept in unheated houses down to -20F and colder, but temps inside these houses are about 0F and warmer and no frostbite.

Seriously tricky business getting ventilation right in cold weather climates!

Note: I edited this post to reflect a change from zone 5a to 6a as the threshold area where a person might want to consider adding insulation. I live in zone 6a and we have already been down below zero about 3 or 4 nights.......and we were hearing reports of frostbite from others living in similar areas at the same temps. Some tight houses with high bird populations seeing frostbite at low single digit F temps. Still, that is only a few nights a year, if that. Or, it may go to -10F or worse a few times, even in zone 6a. On the other hand, zones 5a and colder may see those levels 20 or 30 times over the course of a typical winter. So zone 6a is the threshold to consider it, but probably not needed. Zones 5a and colder probably should include insulation in their build. Goal or purpose of insulation in these houses is to reduce condensation on interior walls, and to reflect radiant heat given off by the birds back into the coop vs. letting it be absorbed by the uninsulated walls to radiate out into the cold. Radiant heat trapped in the coop may be enough to raise the temp inside the coop as much as 10 to 20 degrees F over the outside them, and that is enough to bump a -20F outside temp to 0F, and lower the relative humidity level inside the coop in the process, staving off condensation and drying the house out, and thus reducing the chance of frostbite.

 

[mobius]

@Howard E you described it in so much better detail than i could. So quotable! I am Zone 5b-4a maybe...no insulation. Maybe it would be a good idea for folks to be able to include not just location but climate zones in their avatars.

Can i copy and paste to the "great humidity/ventilation experiment" thread? with your permission? the bathroom metaphor is a great one!

 

[Howard E]

OK by me. BTW, I made some edits to clarify and elaborate on some items. Hopefully making it more understandable.