Coop Design Help - updated

[bangarain]

Hello! For the first time in around 3 years, I'm getting chickens again!
My baby chicks are coming in two weeks, which means preparations are in full swing. While we have built a coop before, the situation is very different now: rather than being build in humid TN with mild winters, we now live in south-central Vermont where the winters get quite a bit more extreme (up to -25 windchill at the worst) and the summers are much more pleasant.
This brings me to the plans I have come up with (please forgive the amateur workup - this was made with less than 24 hours of program knowledge, so I left out most of the angled beams for simplicity. The present ones are there for ease of visualization rather than accuracy.)

The coop is 6x7 ft with 2'3 stilts. The roof is at a 15 degree angle; 7'11 inches at its highest, and about 5'4 at the lowest point of overhang. The human access door is 30"x30", flanked by two 12"x16" windows; either side has 7"x24" vents approximately 3' from the floor, one 10"x14" chicken door, and 5 nest boxes that are about 12" square. This is option 1.

Option two is identical save for the addition of two 12" square windows on the side with the chicken door. Do you think that the addition of these windows would be beneficial in regards to ventilation, or provide too much of a draft? Do note that all windows and vents are framed and lined with hardware cloth, rather than having glass or acrylic panes, but will be able to be shuttered in the winter.

Thank you so much!

 

[3KillerBs]

How many square feet of ventilation do you have in each option? How many chickens do you plan on getting?

It may seem counterintuitive, but people in cold climates need just as much ventilation as people in hot climates. Are you also providing soffit vents at both the top and bottom of the slope?

Supplemental windows for use during the summer are a good addition to the necessary permanent, 24/7/365 vents at the roof level.

 

[bangarain]

I'm not actually sure how to calculate the square footage of the vents. It's probably obvious, but I'm not particularly mathematically inclined when formulae aren't provided.

We plan on housing eight LF chickens - free range, so only locked up at night! We do intend to build a run as winter approaches so in the case of heavy snowfall they will have room to scratch and stretch - but will be focusing on that in a few months.

I forgot to add in my original post that the coop is being built off of the front of our horse barn, so the back of the coop is a solid wall (hence the lack of ventilation on that side!)

 

[bangarain]

Right, so I calculated with a snazzy square footage calculator online and got:
5 square feet and 7 square feet, respectively, chicken door not included.

 

[gtaus]

I live in northern Minnesota. Ventilation of the coop is necessary, even in the winter. I have two windows for cross ventilation and two soffit vents at the peaks of the roof. The important thing to consider is that you have adequate ventilation for the chickens, but not a draft coming up from underneath the chickens when they roost for the night. A draft from underneath the birds will cause them to get cold.

In the winter, the chickens will fluff up their feathers and trap the warm air against their body. If there is a breeze from underneath them, it could interfere with their ability to keep their feathers fluffed up and keep the warm air trapped against their body.

I never shut my soffit vents, but I will close the side windows if a storm with blowing winds is coming in. Then I open the windows when the storm has passed.

There are many advantages to having an elevated chicken coop as in your design. I built my coop on an old boat trailer frame. Having said that, at my age, I sometimes wish I would have just built a walk-in chicken coop. I can walk inside my coop, but I need a few steps to get up into the coop which is on the old boat trailer. Not too much of a big deal as I use a deep litter of wood chips in the coop and really only go inside the coop twice a year for cleaning, and maybe every other month for some kind of maintenance.

I would encourage you to consider using deep litter in your coop. I don't see that built into your design. If you are interested in deep litter, YouTube has a number of video put out by Carolina Coops. I built my coop using lots of their ideas for deep litter coops. I have a drop down gate in the back of the coop so I can just shovel/push out the old litter when I do my twice a year cleanout. Super easy and fast.

I wish you the best of luck with whatever design you decide to build. Keep us updated on your project. Please post some pics as you work on your coop and run.

 

[3KillerBs]

Right, so I calculated with a snazzy square footage calculator online and got:
5 square feet and 7 square feet, respectively, chicken door not included.

For 8 chickens you will want 8 square feet of permanent, 24/7/365 ventilation, preferably located above their heads when sitting on the roosts -- which is the key to not getting frostbite in a cold climate.

I strongly suggest adding open soffits (covered in hardware cloth), to help achieve this.

I would encourage you to consider using deep litter in your coop. I don't see that built into your design. If you are interested in deep litter, YouTube has a number of video put out by Carolina Coops. I built my coop using lots of their ideas for deep litter coops.

I have an article on Using Deep Bedding in a Small Coop.

 

[bangarain]

That's brilliant, @gtaus! I had completely forgotten about accounting for the deep litter method! Here's an updated version, allowing for 12" of litter.

@3KillerBs, I'm not entirely sure where I can fit that much! The size of the door and slant of the roof don't really allow for much ventilation in the front - although I suppose I can sneak some in above the frontal windows, and some smaller vents above the existing ones on the sides? I will try editing and see how much I can fit in.

EDIT: I just noticed that my frontal windows are lopsided! Please ignore that, I'll fix that now, lol.

 

[bangarain]

Alright, so I've edited and tweaked and edited and the best I could get was approximately 7.73 sqf of permanent ventilation.

Modifications:
extended vents on the side to 3'11" x 7"
added vents on the front above windows and just below roof (approx. 18"x3", 6'4x3", marked in red).
I might be able to sneak in some circular vents above the side vents during Real Life Construction. We'll see.

 

[gtaus]

For 8 chickens you will want 8 square feet of permanent, 24/7/365 ventilation, preferably located above their heads when sitting on the roosts -- which is the key to not getting frostbite in a cold climate.

In general, I would agree with those statements. However, I know in my coop, I have broken most of those rule of thumbs without any negative effects. I think there are many factors that play into the ventilation rule of thumb.

I have 10 chickens, so you might think I should have 10 square feet of ventilation for the coop. I only have about 3 square feet of ventilation. My 2 side windows have about 1 square foot of screen each, but the cross ventilation nature of their placement seems to be very good. My soffit vents are each about 6 inches by 12 inches, or maybe another 1 square foot of ventilation for the soffit vents. That adds up to about a total of 3 square feet total for the coop where I have 10 chickens.

But, I have my 10 chickens in a coop that is almost 80 square feet, so about double the coop space recommended for full sized chickens. I overbuilt my coop because in our northern Minnesota winters, my chickens will not go outside in the snow for months. So I doubled the size of my coop in anticipation that the chickens would be spending most of the winter in their coop. @bangarain, you might want to consider your coop size and also add on more room if you expect harsh winters and extended periods of time that your chickens will not go outside. For me, that is at least 3 months out of the year, and usually longer.

The other thing I think really helps with my ventilation is that I have a gambrel style roof. There is a lot of empty air space above my chickens. From their roost to the peak of the roof, there is about 3 feet over their heads. This allows for any humid air to rise up above them and vent out the soffit vents at the peak of the roof.

The first winter I was very concerned about the humidity level in my coop given that I only had 3 square feet of ventilation in the coop for 10 chickens. So I put a temp and humidity sensor both inside and outside my coop. I discovered that there was virtually no difference in either temps or humidity. Given that fact, I feel confident that my coop is adequately vented.

Having said that, I was also surprise to discover how humid our winter weather is outside. I was thinking the humidity would drop down into the low 30%'s like it does in the house. However, I was reading 70% and more humidity outside. Cold and humid are the ingredients for frostbite, but I can't dry out the great outdoors. Some of my birds did get frostbite that first winter, but they recovered. This past winter was less harsh and none of my birds suffered frostbite. But, in my mind, I can't expect my coop to be less humid than the outside air so my chickens have to have the breed characteristics to tolerate our cold winter weather, including possible frostbite.

In sum, ventilation is very important, but many things can factor into properly venting a coop including how many chickens you have, how big the coop is, and the method your coop will naturally vent.

 

[3KillerBs]

@3KillerBs, I'm not entirely sure where I can fit that much!

Adding the vents under the roof that you marked in red was good, but instead of the little rectangles on the sides, open the entire peak triangle -- that's where the warm, moist air needs to be vented out.