It's sad to hear such mis-information coming from that kind of source.
I suppose it might be valid for commercial setups that wants eggs all year around.
The info about using petroleum jelly to prevent frostbite is also not accurate.
I've had chickens for 10 years in prolonged freezing temps...
Looking forward to seeing more pics.
That's a pretty big door, both sides are kept open?
Coop is pretty short, can't ventilate high above roost.
Here's how to add your general geographical location to your profile.
It's easy to do, and then it's always there!
Depends on where the wind is coming from, and if your run has a roof.
Post pics of your coop and run, inside and out, for some more pointed advice.
More chickens to 'heat' a coop is a fallacy.
A well ventilated coop will not 'hold heat'....and most a birds heat is kept under their feathers.