One good laying hen will lay 1 egg a day, every day. So two chickens will give you 14 a week. Here in the Midwest when it gets real cold chickens will stop laying or when they "molt" losing their feathers.
So you need three birds, two hens and a rooster?
some guys use lights and heat lights in the coops to keep chickens laying through the winter.
I like to give my hens an offseason just like ballplayers. Heal up and come out in the spring swinging.