Will my coop be warm enough this coming winter?

[IAMADOL]

So we're building a coop from plans we bought. It's almost done (Thank you God!) It has OSB on the floor and roof. The sides are made of siding which seems a bit flimsy as far as weather goes to me. There is a rectangular vent which is covered with hardware cloth (14" x 4"). And two windows which lock tight. I live in zone 7. Washington state. So we have winters which are mild and winters which are very wicked (four feet of snow in one month one year).
I could make a cover for the vent in winter....But do you think the rest would do or is a heat lamp a requirement? In short, how do you determine whether the birds are warm enough?

 

[Ol Grey Mare]

Don't cover the vent - ventilation is just as important (if not more) in the winter. Supplemental heat is not necessary for otherwise healthy birds of most standard breeds. Your coop is about providing the birds a draft free escape from the elements where they are dry and can allow their own bodies to do what they are designed to do in keeping them warm and toasty.

 

[Clemsonchickfan]

I would be sure to cover the osb floor with something to protect it from moisture (like linoleum). Osb tends to degrade over time when it gets wet.

 

[IAMADOL]

I do have linoleum on the floor. Sorry! Forgot to mention that.