Insulating

I suggest adding insulation. If you want to learn more, you can visit this site
https://www.backyardchickens.com/a/insulating-your-chicken-coop

 

If you install insulation, you will also have to install interior walls. Otherwise, the chickens will shred the unprotected insulation. But, if you have interior walls in a chicken coop, you will have provided a nice hidden place for mice, insects and other pests to set up house for themselves, unseen by you. I don't have any insulation in my coop, after all, the chickens already come with excellent insulation of their own. They need no help from us there. I see you are going to use glassboard on the floor. Is the coop going to be big enough for you to go in? If so, I would not use glassboard, I would think that would make for a slippery floor.
Jack

 

Pennsylvania winters are relatively mild. You really don't need insulation. The key to any livestock is to provide a well ventilated space that is sheltered from elements and predators. Dry and draft free is all you need. I live in northern New Hampshire, no insulation, no additional heat and have no problems with that. I do have a heated water dispenser that's been plugged in for a week now.

A really good thread where those in northern climates and even Alaska weigh in their opinions and experience is: https://www.backyardchickens.com/t/421122/think-its-too-cold-for-your-chickens-think-again

This thread has been running for two years now and still promoting no insulation or added heat.

On a side note about your coop, by hardboard do you mean sheetrock? I'd not recommend that at all. Chickens will peck that up something fierce and if you plan to hose out the coop you don't want sheetrock. The side walls of a coop don't get dirty really and my thorough cleaning that entails hosing the interior clean is only once per year. You could paint the interior studs and walls or use the FRP (fiber reinforced paneling) that your using on floor for walls too. I just used shellac on my floor to seal it and of course 3-4 inches of pine shavings.

 

Vinnie, you can use the hardboard, heck any hardboard, used stuf toof, just paint it if need be .OSB or plywood painted too, ask at your local "Lumber Yards" for top sheets I just bought 2 for like $10.00.
As for rodents and insects, seal all, make sure you have tight fits on corners, possibly clad entire bottom of floor joists, and raise off ground, got any cats that can go under and take care of the meeces.
Insulation may not be 100% necessary in you jurisdiction, but it is nice for holding heat, and keeping out the heat of summer, not sure if insulating just the ceiling might be a good bet in you area,if you are not planning on ceiling insulation, forget about the walls, it won't be much value with any rising heating going out the roof. Create adequate venting, eliminate drafts, good dry bedding, correct volume of chickens, all should be good. I hope all works out, I cannot see our relatives a few generations back, being so concerned about chicken coops, but survival and running the farm was important, it was not a hobby for those folks...

 

I like your coop Jack, and the idea of no insulation, but not sure it would work here in Manitoba Canada(north dakota type weather), -40 is bound to happen a few nights each winter, and -25 to -30, a lot of nights too.
I dunno, most people have insulated coops up here, mice problems, maybe and maybe not. I have a few building here insulated no mice, or insects, but the walls are stuccoed, but again no grain or chickens in these buildings.
I would have a coop without insulation possibly, if I thought I could get away with it in this climate, and I have only Bantams, being small, they don't throw much heat......RR

 

Yeah, -40 sounds pretty cold to me. In the book that I got my design from, it said that coops like it were used up through Maine and Canada. But I don't know about -40. But still, you have to maintain proper ventilation/fresh air, in the winter also. So if you have your coop properly ventilated, it's still going to be close to the outside temp anyway. Unless you are running a heater, but that is a whole other story in itself. I do see the point of insulating up under the roof, to help with the summer heat though. I'm kicking around the idea of adding styrofoam sheets for my coop's roof. The shingles really suck up the summer sun. Other than that, the coop will stay as it is.
Jack

 

I'm a huge fan of roof insulation if your in the southern states. Anywhere you get 100F regularly you'd want your coop in shade or rigid insulation right under the roof. Chickens can not stand heat period. Even your Mediterranean varieties like Leghorns or Anacona can't stand an over heated coop. On the flip side I've had leghorns in my -30F winters which faired fine excepting the touch of frost bite due to over sized combs. These type of birds and most roosters just need a smearing of petroleum jelly on their combs for those super cold nights to act as insulation. Note that chickens bred for cold climates have more feathers and smaller combs. At -10F the Leghorns would be out on the snow pecking about rather than in the uninsulated coop. At -30F nothing wants to be outside even us humans. Those are the days you don't hear any wild life as everything is hunkered down waiting it out; the sound of your feet falling on crusty snow echoes across the land. That's just nature.

ETA: Forgetting to add that high fat content in cold weather is a big plus. Not unlike Eskimos eating whale blubber or feeding your winter birds suet what I feed my chickens is Black Oil Sunflower Seed, aka BOSS. This seed is a super high fat content with 14% protein. I buy a 50lbs bag for 6-8 chickens every winter as a daily treat feed.

 

I'll put it this way, Western Canada with the exception of BC coastline, has bitter winters, not always -30 and -40, but many days of 10f to -10f, very typical, but dry. Minnesota and ND, as well as Alaska knows this weather.
But all the old chicken coops , were never insulated, lots of straw, and things were tough no doubt.
WE get super hot summers too, 90-100f, with humidex of 100+, so birds would be not too happy with that, but it usually is about a month to 6 weeks. I would say your coop Jack would be fine here too, but may need a brooder heat lamp or 2 for those sub-zero times.
Hey it's close to 50 here today, when it should be 20s.....