If you look at the forums "Chicken Behavior & Egglaying", "Managing Your Flock" and "Feeding & Watering your Flock", you will find that quite a number of the recent posts are titled something to the effect, "Why are my chickens not laying?". Lots of people are experiencing it right now. The main reason is the short days (the shortest day of the year was just about a week ago in the northern hemisphere). By as @sweetbeak pointed point, other stresses can cause it. Actually, extending a coop size could be a major stress to many chickens. The noise of extending it along with the fact that their home no longer feels the same. It may feel better to the owner, but not likely to the chickens, at least not right away. Though they will get used to it fairly quickly. "Getting used to it fairly quickly," doesn't necessarily mean they will start laying again soon, though. These chickens can be finicky!
There are a LOT of reasons why a chicken might stop laying eggs. Darker days is #1 reason. Stress is #2. What defines "stress" can be highly individual, not necessarily defined by breed, though it can be. Some birds will stop laying if you switch their food, others won't. Some will stop laying during the dark days of winter, others will simply slow down.