Best coop size for cold climate

[Poppy Putentake]

I'm planning on building a coop for a flock of (what will be) probably between 5 and 10 hens. In the winter, overnight low temperatures here (Vermont) are somtimes below zero Fahrenheit, and can occasionally get as low as minus 20 F.
I've seen the advice to err on the side of making coop on the large side, and it makes sense, but what is the ideal coop size if it gets very cold? Can a coop be too large for the flock to warm with body heat? I've noticed that when it is warm, the birds will tend to spread out in the coop at night (and split up to use both the small and the large tractor), but in mid-winter, they tend to stay close together and will even sleep two (or three!) crawled together into one nesting box! (Note: when it gets that cold, the droppings freeze, so it is easy to remove them from bedding, and they stop sleeping there in the spring, so it's not a big problem.)
Another issue is that my current hens seem very pecking-order-conscious about roosting bars, and usually will only share with another hen from the same brood (i.e., reared together as chicks), so in the new coop I'll be trying to have multiple short roosting bars instead of just a couple of long ones. What is others' experience with this?

 

[DobieLover]

what is the ideal coop size if it gets very cold?

As big as you can make it but realistically, shoot for 4 sq ft per bird.

Can a coop be too large for the flock to warm with body heat?

No. You do not want to try to trap body heat in the coop. They do it themselves by fluffing their feathers. You need the coop DRY and very well ventilated with no drafts on the roosted birds.

What is others' experience with this?

This:

Having that large run with the solid roof being as predator proof as the coop is an extremely useful feature for long, cold winters with lots of snow. The flock pretty much stays in there for the winter. I never close the pop door between their coop and run so they can come out and eat as soon as they are off the roost.
I keep all the food and water in the run. The walls of the run get covered with reinforced opaque poly tarps for the winter to block the wind. It lets some light in and on a sunny winter day it will feel noticeably warmer in the run than outside it.

The space between the soffits and the gable peaks are open year round and secured with 1/2" hardware cloth.
There is also a ridge vent, two cracked open windows away from the roosting area and two pop doors open year round.
The windows next to the birds are a little leaky and that's just more ventilation for winter. There are not drafts at roost level that open feathers. These roost level windows are very much appreciated during the summer when they are kept wide open for cross breezes through the coop.
Note that all of the roosting space is the same height. No bickering over the highest roost.
My flock is multi-generational and they mix together somewhat randomly. Three of the original ladies all like to roost where that buff EE is (she is one of them) but they have accepted the 7.5 month old cockerel and one of his sisters roosting among them.

 

[RoyalChick]

As big as you can make it but realistically, shoot for 4 sq ft per bird.

No. You do not want to try to trap body heat in the coop. They do it themselves by fluffing their feathers. You need the coop DRY and very well ventilated with no drafts on the roosted birds.

This:
View attachment 3066687
Having that large run with the solid roof being as predator proof as the coop is an extremely useful feature for long, cold winters with lots of snow. The flock pretty much stays in there for the winter. I never close the pop door between their coop and run so they can come out and eat as soon as they are off the roost. I keep all the food and water in the run. The walls of the run get covered with reinforced opaque poly tarps for the winter to block the wind. It less some light in and on a sunny winter day it will feel noticeably warmer in the run the outside it.

View attachment 3066690
The space between the soffits and the gable peaks are open year round and secured with 1/2" hardware cloth.
There is also a ridge vent, two cracked open windows away from the roosting area and two pop doors open year round.
The windows next to the birds are a little leaky and that's just more ventilation for winter. There are not drafts roost level that open feathers. These roost level winters are very much appreciated during the summer when they are kept wide open for cross breezes through the coop.
Note that all of the roosting space is the same height. No bickering over height.
My flock is multi-generational and they mix together somewhat randomly. Three of the original ladies all like to roost where that buff EE is (she is one of them) but they have accepted the 7.5 month old cockerel and one of his sisters roosting among them.

Yes that ^.

I am in Northern NJ so a bit milder but still plenty cold. The bigger the better. When we are snowed in my ladies can hang out in the coop and predator proof covered run and when it is really windy they hang out in the coop. I think they would squabble if it was smaller and they were confined that way.

 

[aart]

As big as you can make it but realistically, shoot for 4 sq ft per bird.

Or twice that if you won't have a weather proof run.

 

[3KillerBs]

As big as you can practically make it. I'm in a hot climate rather than a cold one so no personal experience, but I wanted to make sure you have seen this article: https://www.backyardchickens.com/articles/cold-weather-poultry-housing-and-care.72010/

 

[Poppy Putentake]

Hi DobieLover
Thanks for your reply. I like the looks of your coop interior! Do you have any words about various critical dimensions (distance of rooting boards from wall, height of roosts, etc.)? That is a good kind of information to have when building a coop.
Do you have protection for your outdoor run from digging predators? I was thinking of making a portable run cover (sort of a movable mini-greenhouse) for the hens to spend the day in the winter, but that they would not have access to at night, and maybe not even have it imediately adjacent to the coop. (They don't mind walking short distances across packed snow.)

3KillerBs

Thanks for the link to the Alaskan article. He does have a point about the disadvantages of exterior nestg boxes in a wet, snowy clmate. (I was planning on interior nesting boxes, but with eterior access through the wall.)

Also, I saw this thin whte plastic sheeting at a lumberteria and was thinking it would be good for lining the interior of the coop, as it would help keep things clean, and reduce drafts and condensation. (The manufacturer does not recommend it for exterior use, but I did make a cover for something out of it and it has held up okay outdoors for 6 months.) Would a double wall be a place for rodents and bad for that reason? What about lining the roof only?

​

 

[3KillerBs]

Do you have any words about various critical dimensions (distance of rooting boards from wall, height of roosts, etc.)? That is a good kind of information to have when building a coop.

Here are some of those numbers. Not all of them, but some: https://www.backyardchickens.com/articles/coop-stack-up-how-high-stuff-works-well.73427/

Would a double wall be a place for rodents and bad for that reason? What about lining the roof only?

Insulation is, in general, a great place for rodents to nest and not of much use to the chickens. If you have adequate ventilation it's not going to be significantly warmer in the coop than out.