I agree, it's way, way too small and completely lacking in ventilation.

My 4-hen coop is bigger than that!
The usual guidelines per adult, standard-sized bird, and in VT with your heavy snowfalls you will want to go beyond the minimums, are:
4 square feet in the coop,
10 square feet in the run,
1 linear foot of roost,
and 1 square foot of permanent, 24/7/365 ventilation -- the pop door that's closed at night and windows that are closed in the winter don't count.
So for 8 hens that's a 32 square-foot coop, 80 square feet of run, 8 feet of roost, and 8 square feet of draft-free ventilation.
You'll want the base to be deep enough for a decent thickness of bedding^, the nest boxes above the top of the bedding, the roosts above the nest boxes, and the ventilation over the birds heads when they are sitting on their roosts.
It's a shame that people take advantage of new chicken keepers' lack of knowledge.^^ Good for you that you came and asked for advice! I hope we haven't confused you too much.
^My Article on Deep Bedding for small coops:
https://www.backyardchickens.com/articles/using-deep-bedding-in-a-small-coop.76343/
^^I agree that a builder selling chicken coops should be held responsible to know what sort of accommodations chickens actually require.