This is only my third winter with chickens, so I really don't have a feel for what is the "norm."
But what I can tell you is that I've been getting only about 6 eggs out of my 15 hens lately, and two of those eggs are ALWAYS my little production reds. They are reliable layers.
My other 13 hens are an assortment of barred rocks, buff orpingtons, EEs, EE/barred rock mix, and Delawares. Out of this group of 13, the last two days I only got 4 eggs per day. Other days, I might get six eggs out of this group.
But seeing that until recently I was getting 10 to 12 eggs every day, this is a noticible drop.
(Note: I provide ample extra light, so that they get 14 hours of light every day).